CIHM 
Microfiche 
Series 
(Monographs) 


iCMH 

Collection  de 
microfiches 
(monographies) 


Canadian  Institute  for  Historical  MIcroreproductions  /  Institut  Canadian  de  microreproductions  historiq 


ues 


1996 


§■ 


Technical  and  Bibliographic  Notes  /  Notes  techniques  et  bibliographiques 


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r/l   Coloured  plates  and/or  illustrations  / 

D 
D 
D 


noire) 


D 


D 


Planches  et/ou  illustrations  en  couleur 

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n 


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Univaraiti  de  Montrial 

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Univ«r*it<  da  Montreal 

Les  images  suivantes  ont  «t«  reproduites  avec  le 
plus  grand  soin,  compte  tenu  de  la  condition  et 
de  la  nettetA  de  l'exemplaire  film*,  et  en 
conformity  avec  les  conditions  du  contrat  de 
filmage. 

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plat,  selon  le  cas.  Tous  les  autres  exemplaires 
originaux  sont  filmte  en  commen^ant  par  la 
premiere  page  qui  comporte  une  empreinte 
d'impression  ou  d'illustration  et  en  terminant  par 
la  derniAre  page  qui  comporte  une  telle 
empreinte. 

Un  des  symboles  sulvants  apparaltra  sur  la 
darniire  image  de  cheque  microfiche,  selon  le 
cas:  le  symboJe  -♦'  signifie  "A  SUiVRE",  le 
symbole  V  signifie  "FIN". 

Les  cartes,  planches,  tableaux,  etc.,  peuvent  Atre 
film6s  i  des  taux  de  reduction  diffirents. 
Lorsque  le  document  est  trop  grand  pour  dtre 
reproduit  en  un  seul  clich*,  il  est  film*  *  partir 
de  Tangle  supArieur  gauche,  de  gauche  *  droite, 
et  de  haut  en  bas,  en  prenant  le  nombre 
d'images  n*cessaire.  Les  diagrammes  suivants 
illustrent  la  m*thode. 


1  2  3 


1 

2 

3 

4 

5 

6 

THE  FUNDUS  OCULI 
OF  BIRDS 


THE  FUNDUS  OCULI  OF  BIRDS 

ESPECIALLY  AS   VIEWED   BY  THE 

C  PHTH  ALMOSCOPE 


A  Study  in 
Comparative  Anatomy  and  Physiology 


BV 


CASEY  ALBERT  WOOD 


ntulrattd  by  US  drawing!  m  the  text;  alto  by  rixiy-ont 

colored  paintingt  prepared  for  thit  work  by 

Akthuk  W.  Head.  F.Z.S. 

LondotK 


CHICAGO 

THE  LAKESIDE  PRESS 

1917 


CofTiiioiiT,  1!)|7,  iir 
CA!*KV  AI.BKKT  WOOD 


-     0 


TABLE  OF  CONTENTS 


I 

II 
HI 


IV. 


V. 


VI. 


VII. 

VIII. 
IX. 


X. 

XI. 

XII. 
XIII. 


IfAUH 
NTHOhlCTION 

vS.MMA|lv    or    CoNfLlMIONH  J 

(:<.LLK(  TIO.V.  SkLWTION   AND  PnKPAHAT10.N<)r MaTK 
MIAI, 
HlHI.KKHIM  HI 

.\  Hkmf.w  „r  Tii»;  .\natomy  and  Piiyhiolooy  or  the 
OiuiASH  AM>  Tis.m  t:.,  heks  i.n  the  Fcndi  ,«  Ikvu 

(>y    TIIK    HiKI) 
<••       TMALM..Hr..l.V,     „»     TIIK      KxAMISATK.N      TllHOt  (iH 
IIIK  I'ri'lLH.  IN  .\mmatK  Si'K<  IMKNs.  of   TIIK  l.NTK- 
moH   UV   TIIK    \KHTKill(ATE   KvK    HV  MeaNS  OE  THE 

<)i'iiTiiALM()S(()ri: 

«)i-iiTiiAiMo.s,.o,.v  OK  THK  FiM).  H  IN  L,v,N„  lUnns:  83 

.\       rho  Ky«-Krr>,iii(l  in  Ccncral 35 

H      The  I'cctcii  iiiiil  Optic  Disc  gg 
<'.     TL.'  .Macular  UcKions,  Fovea-  anil  otlicr  .\rtNis 

of  Acute  Viiioii       .      ,  jjg 
I).     The   Fuiidal   nioo.lvcys.-ls,   the  Opaqu.-   \,-rvc 

Fil)r.-s,  the  Choroid  aii.l  the  lietina  38 

K.     riiolo^rraphy  ..f  the  Fun.lus  in  I.iviiin  Birds  44 
•Ma.  Kos<  opic  Api'eara.vc  Es  OK  THE  F      urs  OctLi  or 

UiHDs  IN  Phepaiied  Spe(  imens  49 

l'hot..jfraphy  of  the  Fundus  in  P        red   Eyeballs  01 

fcKKE.TH    OF    D0MK.STICATION    ON    THE    FlNW.S    Ot  ILI 

OK  Wild  Spe(  ie.s  of  Bihd.s qj 

The  Ophthauvio-scopic  and  Ma.  Hos.i.Pt,  Appeak- 
ANCEH  or  THE  FlnDUS  Oil  LI  IN  \ahiol.s  <)hdeh.-s 
or  Birds. 

A.  Uutitip _. 

B.  Carinata- fls 

CLA.S.SIF1CAT10N  or  the  OciLAR  FixDi  ok  Birds     '     112 
The  ().iTL.4R  FuNDia  or  Birds  in  its  Kelation  to 

A    Cla.-SSFICATION   of  AvES  .14 

The  Relations  ok  Reptilian  to  Avian  Findi  uq 

Colored  Drawings  of  the  Fundus  Ocuu  of  Birds     119 

Colored  Drawings  of  the  Fundus  Oculi  of  Reptiles       178 


Chapter  I 
INTRODUCTION 


Althouoh  the  ophthalmoscopic  and  naked- 
eye  appearances  of  the  fundus  ocuii  liave  been 
thoroughly  described  and  depicte<l  by  other 
writers  in  many  of  the  Mainniiils  —  espe- 
cially in  Man —yet  very  little  attention  has 
been  paid  to  the  remarkable  and  interesting 
eyegrouuds  of  the  animal  that  exhibits  the 
highest  and  most  varied  types  of  vision  — 
the  Bird.  The  meagre  accounts  given  by 
even  modern  writers  of  the  appearances  of 
the  avian  fundus  are  probably  due  either  to 
their  quoting  the  ill-formed  opinions  of  early 
observers  or  to  their  ignorance  of  the  proper 
use  of  the  ophthalmoscope;  facihty  in  the 
employment  of  this  instrument  is  acquired 
only  after  long  practice,  and  it  is  not  to  be 
expected  that  every  zoologist  can  make  his 
own  notes  of  fundus  pictures. 

The  main  purpose  of  this  study  is  to  furnish 
such  a  description  of  the  intraocular  appear- 
ances and  the  methods  employed  in  viewing 
them  as  will  enable  other  ophthalmologists 
and  zoologists  to  further  this  study  by  ex- 
amining the  eyegrounds  of  Birds  that  come 
under  their  observation. 

The  eyes  of  some  representative  of  (prac- 
tically) all  the  Orders  of  Birds  and  most  of 
their  backgrounds  have  been  examined  by 
the  writer;  and  are  more  or  less  fully  de- 
scribed and  illustrated  in  this  Atlas.  More- 
over, some  of  the  more  important  species 
were  examined  not  only  ophthalnioscopically 
before  death  but  macroscopically  afterwards. 
In  addition  to  these  methods  of  investigation 
extensive  microscopic  examinations  of  the 
tissues  were  carried  on,  especially  in  conjunc- 
tion with  Professor  J.  R.  Slonaker. 

That  this  research  might  have  a  broader  and 
more  useful  application  the  writer  has  also  ex- 


l«] 


amined  the  ocular  fundi  of  a  number  of  species 
of  other  vertebrate  orders.     A  brief  compari- 
son will  be  made  between  a  few  of  these  find- 
ings and  those  discovered  in  the  avian  fundi. 
The    writer   is    much    indebted    to   many 
colleagues  and   other  friends  for  assistance 
in  carrying  out   the  present  investigations, 
which  he  began  more  than  ten  years  ago. 
Among  these  are  the  officials  of  the  London 
Zoological  Society,  Mr.   Chas.  H.   Hicks  in 
particular;  Professors  James  R.  Slonaker  and 
Frank  W.  Weymouth  of  Stanford  University; 
Mr.  C.  \V.  Beebe,  of  the  New  York  Zoloogical 
Park;  Mr.  Cy  de  Vry  of  Lincoln  Park,  Chi- 
cago, and  the  officers  of  the  Golden  date  Park, 
San  Francisco,  California;  and  Mr.  Arthur 
W.  Head  (the  well-known  artist)  who  has  so 
ably  depicted  and  reproduced  in  this  work 
the  avian  fundi  therein  described.     His  thanks 
are  also  due  to  Mr.  C.  H.  Kennedy,  now  of 
Cornell  University,  who  has  drawn  so  faith- 
fully most  of  the  black  and  white  figures  in 
Chapter    VH,    illustrating   the    macroscopic 
findings  of  preserved  specimens.     He  is  also 
under  obligations  to  Mr.  Douglas  Fyfe,  who 
nuide  for  him  a  collection  of  birds'  heads  in 
the  United  States  of  Colombia;  to  Lieut.-Col. 
J.  W.  Barrett  of  Melbourne,  who  performed 
the  same  service  in  Australasia,  and  to  a  num- 
ber of  Californians,  among  them  Messrs.  Van 
Rossem,    Wright    M.    Pierce,    R.    H.    Beck, 
Lieut.   Casey  Hayes   (U.   S.   Army)and  the 
Managers  of  the  Cawston  Ostrich  Farm  and 
Bentley  Ostrich   Farm,   who  furnished   him 
with    abundant    material    from    the    Pacific 
Coast.     He  also  owes  his  thanks  to  Professor 
J.  Grinnell  for  the  loan  of  material  from  the 
Museum  of  Vertebrate  Zoology  of  the  Uni- 
versity of  California;  to  Dr.  T.  A.  Woodruff 


6 


THE  FUNDUS  OCULI  OF  BIRDS 


who  assisted  him  in  his  earlier  ophthalmo- 
scopic studies  of  Birds,  and  to  Professor  Henry 
B.  Ward  of  the  University  of  Illinois  foV 
assistance  in  reading  the  proof  slu-ets  as  thev 
were  passing  through  the  press. 

The  systematic  classification  employed  for 
the  purposes  of  this  work  is  that  of  Bowdlcr 


Sharpt-s  Hand-List  of  Genera  and  Species 
(London.  19(19).  except  that  in  mentioning 
•North  American  Binls  the  spwific  names  on 
tlie  (heck  List  of  the  American  Ornitho- 
logical Union  (1910)  has  been  used. 

Ca8ey  a.  Wood. 
Chicago,  1917. 


Chapter  II 
SUMMARY  OF  CONCLUSIONS 


1.  The  examination  of  the  eyes  of  Birds 
is  a  study  of  tlie  most  ad'anced  and  most 
varied  apparatus  for  the  highest  expression 
of  vision  known  to  any  vertebrate  class. 

i.  The  examination  of  the  interior  of  the 
avian  eye  through  the  pupil  of  animate  species 
(ophthalmoscopy)  gives  valuable  information 
regarding  the  function  of  sight  in  general  and 
of  the  eyesight  of  Birds  in  particular. 

3.  The  fundus  oculi,  or  background  of  the 
eye,  is  plainly  seen  in  its  normal  relations 
when  \iewed  during  the  life  of  the  species, 
and  in  many  respects  this  form  of  exploration 
is  superior  to  methods  carried  out  on  prepared 
or  preserved  eyeballs. 

4.  The  parts  and  organs  visible  by  the 
ophthalmoscope  in  the  eye  of  the  Bird  are  in 
particular  (a)  the  concavity  or  general  chorio- 
retinal surface  of  the  posterior  half  of  the 
eye;  (fc)  the  ijecten;  (c)  the  optic  nerve  en- 
trance; (rf)  the  areas  of  acute  vision;  (e)  the 
fundal  bloodvessels;  (J)  opaque  nerve  fibres. 

a.  The  appearances  of  these  organs  and 
tissues  furnish  entirely  different,  colored  fun- 
dus pictures,  and  it  is  frequently  possible  to 
recognize  a  species  by  viewing  its  fundus 
oculi. 

<>.  The  fundus  oculi  of  Birds  exhibits  a 
great  variety  of  areas  of  distinct  vision,  and 
the.se  correspond  closely  to  the  habits  and 
habitat  of  these  animals  —  especially  their 
methods  of  obtaining  food,  of  escape  from 
enemies,  of  migration,  of  reproduction,  etc. 

7.  In  spite  of  recent  advances  in  that  di- 
rection, attempts  to  reproduce  the  colored 
(ophthalmoscopic)  appearances  of  the  fundus 
by  photography  have  so  far  failed. 


8.  The  macroscopic  appearances  of  the 
ocular  fundus  resulting  from  an  examination 
of  preserved  .specimens  have  a  value  in  this 
research  all  their  own;  for  certain  forms  of 
examination  it  is  inferior  to  ophthalmoscopy, 
for  others  superior;  but  it  gives  no  indication 
of  the  color  tones  of  the  background  so  well 
shown  by  the  ophthalmoscope. 

9.  As  in  ophthalmoscopy,  attempts  to  re- 
produce the  details  of  the  cyeground  of  pre- 
served specimens  have  so  far  given  unsatis- 
factory results. 

10.  The  use  of  the  niiero.scope  in  examin- 
ing the  avian  eye,  and  especially  serial  sec- 
tions of  the  parts,  is  occasionally  required 
to  settle  anatomical  questions  that  neither 
ophthalmoscopy  nor  macroscopy  can  eluci- 
date. 

11.  Domestication  or  prolonged  captivity 
brings  about  abnormal  changes  in  the  cye- 
ground of  Birds,  so  that  only  healthy,  wild 
specimens  should  !.e  utilized  in  this  or  a 
similar   research. 

12.  As  the  colored  pictures  seen  in  the 
fundi  of  healthy  wild  birds  are  invariable  in 
species  these  appearances  may  well  furnish 
data  for  a  classification  of  Aves  ranking  in 
importance  with  other  taxonomic  indications. 

13.  Ophthalmoscopy  throws  light  on  the 
origin  of  Birds,  or  at  least  on  their  relation 
to  that  Sauropsidian  ancestry  which  they 
hold  in  common  with  Reptilia. 

14.  In  future  no  report  upon  a  particular 
avian  species  can  be  held  complete  that 
ignores  the  visual  apparatus,  and  especially 
the  appearances  of  the  fundus  oculi  as  shown 
by  the  ophthalmoscope. 


[7] 


Chapter  III 


.^pocios  have  been  examined  by  the  writer 
ophthalmoscopicallv  and  otherwise  L^ur 

ma.v  be  the  conditions  found  in  the  fundi  of 
such  b.rds  (especially  of  living  biJds)  as  are 
most  hkely  to  be  useful  in  a  study  of  com 
parative    ophthalmology.     To    this    end    h 
has  confined   his  atteSion   to  nLfJu 

Zl7lt  'r  ^'"'r^'^  avoidTdleTt^ 
cated  domestic  or  otherwise  abnormal  birds, 
it  IS  ...  thcie  more  or  less  tame  species  that 
numerous  variations  from  the  no^al  ey^ 

possTbtr  d7=  -nsequently  it  is  quitel- 
possible  to  deduce  from  fundus  examinat:     , 
of  tame  or  diseased  birds  any  phylwi^^ 
conclusions  worthy  the  name     Th      cE 

animals  t"'tr  ''^  ''^  *"''■    ^-^ticat^J 
ea  ,W   to        ^'   "?*    "^'^'^^^    ^^d    the 

;i:;i:Ju^-d=L;:f:Ss::^ 

numerous  as  to  render  it  impraSbef " 
any  one.  even  m  a  long  lifetime,  to  make  a 
complete  mvestigation  of  the  c^ular  Sack! 

f-ven  in  an  examination  of  the  eves  nt  h;„i 

always  preferable  to  birds  that  hive  bin 
Jong  confined  and  exposed  to  the  unwonSS 
surroundings  of  cage  life.  """wonted 

In  addition  to  such  wild  birds  as  are  acces 
s.ble  in  private  collections  or  that  ZZt 


18] 


found  in  every  zoological  garden  or  park 

he  field  naturalist  may  himself,  or  by  proxy 

trap  or  she.  t  the  specimens  he  ileeds."^  E 

ployed  by  Mu.seums  and  Colleges,  either  as 
duplicates  or  in  conjunction  with  the  cot 
lectors'  other  work.     The  writer,  armed  w' th 

trips  of  this  kind  and  has  in  this  way  been 
able  to  examine  the  fundi  of  many  disabled 
or  recently  killed  birds.  aisabled 

3of  anH'"'7'°°"'  ophthalmoscope  (see  page 
30)  and  a  large  opaque,  black  umbrella  are 
the  most  useful  implements  for  field  woX 
A    ew  minutes  before  and  after  the  death 
of  the  specimen  one  finds  the  pupil  wide  v 
dilated,  so  that  the  ocular  interior  clnt 
readily  exp  ored.     Birds  that  are  un^ur^ 
or  merely  "winged"  are  placed  in  a  box  !r 
cage  and  carried  to  the  laboratory  or  dark 
room,     here    to    be    examined    ophthaJmo 
scopically  at  greater  leisure.     See  cLpS  V? 
for  macroscopic  studies  of  the  fundus  in 
prepared  material  the  bird's  head  shodd 

Pereti'   -a  P''""'^    fl"'d- preferably 
lerenyis-a  few  minutes  after  death.     I„ 

1.  When  possible,  secure  at  least  three 
heads  of  each  species.  2.  Immediately  afS 
death  incise  the  skin  about  the  nelrwel 

from  the  head  by  pulling  it  forward,  wrong 
side  out,  over  the  head,  cutting  the  thin  mem 
branes  about  the  eyes  (at  the  margin  oTt^e 

S  ;  orT"'  '"^■"•!;  ''^  ^^^  ^^^»'«''-     "   he 
ejes  or  their  appendages  are  cut  or  injured 

m  any  way  the  specimen  is  render^  iseS 


COLLECTION,  SELECTION  AND  PREPARATION  OF  MATERIAL 


Diseased  or  i.:jured  eyes  are  also  of  no  use  in 
this  investigation.    3.  After  skinning,  sever 
the  head  from  the  body  by  decapitation  close 
to  the  base  of  the  skull.     4.  Label  the  head 
by  tying  a  string  —  to  which  a  label  is  at- 
tached —  securely   through    the   nostrils   on 
the  beak.     This  label  should   bear,   written 
distinctly  mth  a  hard  pencil,  both  the  eommon 
and  zoological  name  of  the  bird,  the  date  and 
locality  of  collection,  as  well  as  the  name  and 
address  of  the  collector.     Heads  of  the  same 
species  should  be  numbered  serially  (1,  2,  3, 
etc.).     5.  The    foregoing    operations    should 
occupy  as  brief  a  time  as  possible.     The  head 
should  then  be  immersed  in  a  quantity  of 
fresh  I'lrenyi's  fluid  equal  to  twenty  times 
the  volume  of  the  head.     Fruit  jars  are  con- 
venient  containers   for   this    purpose.     For- 
mida  of  Perenyi's  Fluid:  10%  nitric  acid  in 
clean  wate/  (10  acid  to  90  water),  4  parts; 
95%    (commercial   grain)    alcohol,   3   parts; 
0.5%  chromic  acid  in  clean  water  (grni.  0.50 
acid  to  100  cc.  water,  3  parts.     After  a  few 
minutes  this  mixture  turns  a  violet  color. 
It  may  be  kept  in  bulk  indefinitely  if  well 
corked.     6.  Leave    the    heads    in    Perenyi's 
fluid  until  the  hardest  bones  of  the  skull  be- 
come soft  and  pliahS  when  touched  with  a 
scalpel.     The  time  required  will  depend  upon 
the  size  of  the  head.     The  following  periods 
of  immersion  will  usually  be  suflicient:  Small 
heads,  as  sparrow,  robin,  etc.,  24  hours;  me- 
dium sized  heads,  as  the  crow,  36  hours;  large 
heads,  as  the  owl,  48  hours;  extra  large  heads, 
as  the  ostrich,  3  to  4  days.     7.  After  decal- 
cification in  Perenyi's  fluid  the  heads  should 
be  treated  with  the  following  percentages  of 
commercial  grain  alcohol.     In  each  case  use 
approximately    20    volumes   of   the    alcohol 
solution  to  one  volume  of  the  head.     The  best 
results  are  obtained  by  using  fresh  alcohol  solu- 
tion for  each  head.     Leave  the  heads  in  each 
of  these  alcohols  for  the  same  period  they  were 
immersed  in  Perenyi's  fluid.     70%  alcohol  is 
made  by  .nixing  70  volumes  of  95%  (commer- 
cial grain)  alcohol  with  25  volumes  of  clean 
water;  80%  alcohol,  made  by  mixmg  80  vol- 
umes of  95%  alcohol  with  15  volumes  of  clean 
water;  95%  (commercial  grain)  alcohol.     8. 
After  treatment  with  the  last  alcohol  solution 


the  heads  may  be  packed  in  a  fruit  jar  suflS- 
ciently  large  to  hold  them,  covered  with  95% 
alcohol  and  carefully  sealed  to  prevent  leakage. 
Should  the  eyeball  lose  its  rotundity,  or 
"cave  in"  anywhere,  the  defect  may  be  some- 
times remedied  by  injecting  70%  alcohol,  by 
means  of  a  hypodermic  syringe,  into  the 
vitreous  chamber. 

Prepared  in  this  way  the  bones  of  the  skull 
and  the  sclerotic  plates  are  so  softened  that 
sections  of  them  can  readily  be  made,  while 
the  walls  of  the  eyeball  are  so  hardened  that 
they  can  be  bisected  at  the  equator  with  a  sharp 
razor  and  the  anterior  segment  removed,  with 
the  cornea,  lens  and  vitreous.  The  parts 
behind,  in  the  posterior  half  of  the  globe, 
constituting  the  fundus  oculi,  eyeground  or 
background  of  the  eye,  remain  in  situ  and  can 
be  readily  examined. 

Although  injection  of  the  arteries  of  the 
avian  fundus  is  not  as  useful  as  in  those  eyes 
in  which  there  are  retinal  vessels,  yet  occa- 
sionally the  choroidal  bloodvessels  and  (per- 
haps) the  pecten  are  affected  by  it  and  thus 
rendered  more  visible.  In  that  case  prefer- 
ably the  gelatine-carmine  mass  of  Ranvier  is 
injected  by  way  of  the  carotid  arteries. 

In  examining  macroscopically  the  posterior 
segment  of  the  eyeball  a  magnifying  lens  of 
10  cm.  focus  may  sometimes  be  used  but  the 
unaided  eye  is  generally  satisfactory. 

On  removing  the  hardened  vitreous  (by 
means  of  a  mounted  needle)  the  grayish, 
translucent  retina  should  lie  smoothly  on  the 
choroid  when  the  preparation  is  a  success. 
Retinal  wrinkling  occurs  not  infrequently  in 
some  part  of  the  eyeground,  in  which  case  it 
may  give  rise  to  errors  in  determining  the 
presence  or  absence  of  some  of  the  areas  of 
distinct  vision,  etc.  A  well  preserved  eyeball 
furnishes  satisfactory  material  for  man"  vears. 
For  microscopic  sections  a  window  it  in 
the  globe  in  the  plane  of  the  desire.  .ons, 

the  vitreous  removed  without  injury  .o  the 
choroid  and  retina  and  the  cavity  filled  (by 
immersion)  with  celloidin.  However,  as  the 
minutiae  of  this  form  of  investigation  is  out- 
side the  scope  of  this  work  the  writer  must 
refer  the  reader  to  laboratory  textbooks  on 
the  subject. 


10 


THE  FUNDUS  OCULI  OF  BIRDS 


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COLLECTION,  SELECTION  AND  PREPARATION  OF   MATERIAL 


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der  Haustiere,  p.  484,  Sehorgan;  1906. 


iifli 


ii!i 


'It! 


Chapter  iv 

A  REVIEW   OF  THE  ANATOMY   AND   PHYSIOLOC  V  op   Tur- 
ORGANS  AND  TISSUES  SEEN  In'^THE  fS^^^         ^""^ 
OCULI  OF  THE  BIRD 


A  COMPARISON  of  the  ocular  structure.,  in  the 
vertebrate  sub-classes  shows  that  the  jmsterior 
two-th.r,ls  of  the  eyeball  contai..  practically 
the  same  organs  in  all,  with,  of  course,  numer- 
ous modifications  of  them  to  suit  the  visual 
requirements  of  a  particular  species 

In  Vertebrates  generally  the  fundus  organs 
of  especm  interest  are  the  retinal  and  chormdal 
bloodvesseh  (in  some  instances  p- ejected  into 
the  rt/r^o«*  humor),  the  choroid,  the  retina 
and  the  optic  nerve  entrance,  the  last  named 
otherwise  known  as  the  optic  di.c,  poms 
opticus,  nerve-head  or  papilla. 


Although  the  ret  ,«l  layers  are  generally 
transparent,  an.l  not  visible  during  life,  vet 
this  IS  not  true  of  all  species;  e.g.,  occasionally 
n  certain  number  of  translucent  nerve-fibre 
sheaths  (neurilemmata)  are  prolonge.1  into 
ttie  retina  and  variously  distributed  over  the 
background  .,f  the  eye.  and,  by  „,ean.s  of  (h.- 
ophthalmoscope  especially,  are  visible  and 
have  been  described  under  the  name  medul- 
lated  or     opaque"  nerve  fibres. 

These  organs  ano  tissues  will  be  considered 
in  their  order. 


Fig.  1 

English  Sparrow.    A,  area  centralis;  F.  fovea-  O  onH. 

^erjinr /' r*-^    Thep^.rrdsVnfo 
vertical  in  this  6gure.    (Wood  and  Slonaker.) 


fl«) 


ANATOMY  OF  THE  FUNDUS  ORGANS  IN  BIRDS 


IS 


J 


tT 


rill 

PI 

il3 


Jl 

^  o 

1.1  s 


Z    ,-3 


u5 


I 


14 


THE  Fl'NDUS  OCULI  OF  BIRDS 


Fig.  4 

The  Temporal  Mononucular  Fundus  of  the  Great 
Homed  Owl  — Buio  tirginianut.  (After  Slonaker.) 
FT,  visual  axis  of  the  single,  temporal  fovea;  P,  pecten. 


ANATOMY  OF  THE  FUNDUS  OPGANS  IN  BIRDS 


M 


83^11 


isS- 


*• 


Ifl 


TIIK   FlNins  (Mil,!   (»F  BIHDS 


The  Avian  Choroid 

The  i-lniriiHl  •■•'ill  nhiirniiliti)  nf  HinU'  cyci 
'\*  iilwiivi  viTV  tliiti,  v\»-H  ill  liirKi-  ••\«l>iilU, 
lull  lliickiT  tlmii  ill  I  In-  >.  •iiiiiiir'.  i-.Vf.  'rill- 
viiwiiliir,  i;i|<ill.irv  iiii''<ln's  {rlutriiM-iipillnrin) 
iiri'  ;>f  imviiliir  ^i/i'  ami  mIIi^t  nitmiw;  in 
Siriilliiii  III)-  I 'i|iilliirii'H  iiri'  0.01  0.0{  miii. 
wiili'  liriiiiiti'r  lliiiii  in  iitlu'r  liinU.  TIm- 
spiitr^  iK'lwn'ii  th<'  •■iijiilliirif^  iirt',  lu'cfiriliiiij 


i-t  MM-n  III  it*  wiiii-il  iiIkimI  IIm'  liiiK-  ••f  liiii^-li- 
iiiK  (wlii'ii  ilitfi'D'Hliiiliiiri  lakes  plan'  iiio^l 
iM'liM-Iyi  aiul  lii'ciiiiii"*  lliiiiiuT  anil  ri'iiiaiii'< 
|NTiiiiiiifiil  hIii-ii  llif  liini  i-i  M-vcral  iiiniillii 
•>l<l. 

A  lajHlinn  it  aliM  III  in  I'  nU,  alth<iii);li  Ihc 
Niiltiati  (Ktri^'li  liii-<  11  ){lii'''<-lik^'  la.MT  in  th<' 
I'liiiroiil,  of  laiiii'llali'il  '■tniilliri',  inpalili-  of 
rrlli-ctiiig   littlit    ooi!    priMliicing    rulur    inh  r- 


FiR.  7 
MucroiM'opiiHl,   I'iKtiiiortiMii  Diai(r»ni  nf  llii-  liiruliililiiiiuiilnr  Fiiiiilii'i  ami  Orliil  nf  ll»'   Titii   iSlmia  liinindo). 
;',  optic  iicrvo  rntnimt';   I',  [Hftcii;   Ft.  fnvcii  uiiil  iiri'B  li'm|i<>ruli'<;    Fii,  fovea  ami  area  iia»uli«^    Ali,  liaiicl-liki' 

area.     (After  SlonakiT.) 


lo  Franz,  coniplclcly  frf-  of  cells  and  pigment. 
The  aiMiiunt  of  piKiiK-nt  in  lli<>  >.-xtcrnal  layer 
is  sulijcct  tit  viiriati'm. 

The  thickness  of  this  roat  i  Panner  dommti- 
rim  is  alxnit  •iiW  microns.  The  re.turls  of 
the  choriiH'apiihiris  measure  iroiii  10  to  '20 
micriiii.  in  widtii;  lu'tween  I  hem  is  a  finely 
punctate  s  ilistniice.  Thi>  laver  is  7  to  8 
iniirons  thick.  Kxternally  Ih.  re  is  an  endo- 
thelial layer,  then  a  ret  work  of  tine  elastic 
tihres  without  cells  or  pigment;  finally,  a 
dense  plexus  of  connecting!  cell- 

Thc  mnrs  run  within  the  <ii|>rachoroi<lal 
space  and  send  only  fine  filaments  into  trahec- 
ulie  that  form  a  cavernous  system  throughout 
the  whole  coat. 

^■lonaker  found  the  choroid  (o  be  enlarged 
ami  most  vascular  (see  Fig.  1.  just  opposite 
the  fovea,  esjK'cially  in  embryonal  life  <oid 
in  newly-hatched  indi\'iiliials.  It  is  in  the 
fonner  instance  >  ne  uf  th'-  indications  of  the 
spot  where  the  fovea  will  eventually  form; 
then  it  widens  during  the  foveal  formation, 


fereiK'c  etfecN.  This  arrangement,  howext-r, 
is  only  a  retino-choroidal  variation,  and  not  a 
true  ta|H'tuin. 

The  Retina  of  Birds 

Tlie  aculeness  of  the  eyesight  in  Hirds  i> 
largely  ilue  to  the  fineness  anil  close  arrange- 
ment of  Ihc  retinal  elements.     .S-e  Fig.  !>. 

(Justav  Fritscli  (Arrhlr,  \likritxk(:p.  Aniil- 
omie.  Vol.  7«,  p.  'iio,  lilll)  DelievcN  that  true 
rods  and  cones  are  found  in  Birds,  just  a-< 
tli(>y  are  in  Mammals,  and  they  should  lie 
design! 'cd  as  such.  In  Ihc  region  of  the 
fovea  riiitniUn  there  is  also  a  dwarfed,  cone- 
like form.  The  rolond,  riiiiiiil  (Iniphl.s  of 
Birds  apiK'ar  mostly  in  the  rod  elements, 
although  they  are  sometimes  seen  in  conjunc- 
tion with  cones.  .Vmoi.  r  the  ceii'tal  cones  is 
also  found,  quite  commonly,  a  body  which  is 
colored  brown  by  osmic  iK-id. 

.\ceording  to  Franz  (I  ^  VmnUirni'  li)H  ) 
the  layers  of  the  avian  n!  uia  are  more  sharply 
defined  than   in  any  other  vertebrate;  even 


ANATOMY  OF  THE   FrNDI.S  OfUi.WS  I\   nniDS 


niorv  ito  thnn  in  Miininmiv  Tlu-n-  urt-  ni> 
M^pHrntc  lii|H>ltir  or  opticiil  Kmixliori  c-lN  jn 
BiriN,  while  we  flmi  in  Miinimnlt  i'«>liii<,i 
iinmcrinc  n-IN,  and,  in  n-plili"..  lii|K)lii'  ..lU. 
All  liirilt  iMWMi'*,  hmN  ii<  well  .iM  villus. 
iillli<iiit(h  in  v<T,v  iliffrn-nl  iirriint{<  nuiiN. 
11.  Mllllcr  crroiu'iiiivly  ijcpiiiiil  ihi<  tnuvt  of 
the  I'imim  with  loiitf  rjlinilrinil  i-xln-niilie*. 


tk>^-i''.K'M 


mm 


Fifjs.  8,  0  and  10 

The  Retina  of  VarlDiiH  V(rt<'l)riiti'i 

Fig.  8,   Liiard;  Fi«.  »,  Bird  (Common  Crowi;    Vig.   10,   Mummal 

(I)oK).     xilO.     (After  I'.  Chiarini.) 


when  thfsf  rtally  IwIohk  to  tin-  rods.  The 
•  I  IK'S  have  each  a  single  oil  droplet,  whose 
eolor  varies.  Cajnl  tins  ditFereiitiiited  (in 
Birds  and  in  Reptiles)  "slniiKht"  and 
"obli(iue"  eones. 

The  noelei  of  the  cones  usually  lie  inside 
the  iiiembraua  limitann  ixtcnia  of  the  retina. 
.Several  "oblique"  cones  have  an  enlarge- 
ment of  the  en<l  inside  the  inner  layer  of 
nuclei.  The  "twin"  coim-s,  whose  nuclei  are 
not  to  he  seen,  lie  near  the  incmhrana  limitann; 
the  smaller  nucleus  of  the  pair  is  in  a  facet  of 
the  larger.  The  rod  nuclei  are  usually  found 
in  the  internal  half  of  the  nuclear  layer.  Their 
small   end    branches    in    the   outer   reiicular 


layer,  stniehing  out  farther  than  the  iiid  ..f 
the  I'one.     The  r<Hl  ill  niM'tiirnal  bird-,  .n,!, 

"»  •! xteriiiil  portion  nf  the  cnlrr  retirulur 

lii.\er   with   a   niMh.-ily        a   little   ball   ill    thf 
end    without    any    bratiihes. 

•  ajal  ditfenntiales  threo  »u[).rinipo«  d 
plexuses  in  the  eilenial  riiinal  lin/ir;  I  hi'  (ir-.|, 
eoniiHwil  of  the  basal  fibrils  of  the  rod.; 
the  second,  the  en  l-lhr.ad-  of  Ihr 
Kiraighl  (■one^;  the  third,  (ibriN 
which  eiiianali-  from  the  oblit|M<' 
cones,  that  i-  -ry  cell  coine  in 
eonlad  with  Itn  dendrites  of  i  er- 
tain  bi|M>lars  and  loiij^iiiidinal  gim- 
glion  celU, 

.Fust  as  in  lieptiles,  Siliirtrir- 
deeker  found  in  the  Cliiekeii,  (row 
and  (Joose,  in  (he  cvleniid  n-liruhir 
iiMi  tear  layer,  eoiicenl  ric  »upporl  iii>; 
cells  without  nuclei. 

Tllf  iniiir  iincliar  lai/ir  nf  Ihr  ri- 
tina.  One  finds  on  the  extreme 
out<T  as|«'<t  horizontal  KanKlinri 
cellsand  I.))  bru-h-lik<-cell>nf  <  jijid, 
with  many  projections  iiml  a  long 
horizontal  cyliniler  which,  like  the 
short  projections,  tiends  around  the 
outer  reticularis  and  ends  Iherr 
with  an  enlargement  and  lir.iiicli<s; 
(l>  star-like  cells  with  soniewhat 
longer  dendrites  and  a  short  c\  lin- 
der  ieh  first  turns  in  and  then 
ou!.  Hetween.  and  further  in  than 
the  cells,  which  Schiefrerdecker  calls 
-.ucleatetl  cells,  arc  found  two  kinds 
of  bipolars;  first,  outer  bipolars  with  highly 
developed  dendrites,  and  internal,  small  or 
thin  bipolars  with  weaker  dendrites.  The 
thick  bipolars  .seem  to  branch  out  in  the  fifth 
layer  of  the  internal  reticularis;  the  thin 
bipolars  assume  more  the  form  of  a  layer  in 
the  inner  reticularis. 

•Vs  in  all  animals,  the  nuclei  of  the  sup- 
porting fibres  of  Mailer  in  the  avian  retina 
are  situated  in  the  internal  nuclear  layer. 

In  the  inner  portion  of  the  internal  nuclear 
layer  are  found,  as  ganglion  cells,  the  layer 
of  amacrine  cells,  which  are  divided,  both  in 
Birds  and  Biptilia,  into  (1)  nervous  and 
(i)  proper  amacrine  cells. 


18 


The  layer  of  gangUnn  rells.  Cajal  differ- 
ent iatos  tk-  following  ...pes  of  ganglion 
optical  eolls:  («)  single-layere.l  cells,  sprea.l- 
ing  out  over  the  internal  reticular  laver 
partly  nniltipolar,  but  mostly  l.elonging  t(i 
the  reticularis;  {b)  many-layered,  mulliiwlar 
cells.  The  smallest  are  plentiful  in  the 
I  asserifornies;  i.e.,  the  .Sparrow,  Chadinch, 
vireenfineh,  etc. 

It  should  be  noticed  that  Dogiel  e\pres.sed 
the  opinion  that  those  cells  which  in  form, 
size  and  character  of  branching  of  the  pro- 
toplasmal  and  cylintlrical  processes,  belong 
to  a  certain  characteristic  tyin-,  anastomose 
with  each  other,  or  form  a  "colony." 

The  relatively  thick,  optic  conmctire  tw.wr 
receives  single,  dissimilar,  thick  filaments 
which,  originating  centrifugallv  from  the 
optic  nerve,  intermingle  with  the  internal 
plexiform  tissue  and  end,  according  to  Cajal, 
on  the  level  of  the  amacrine  cell-layer. 

Specifc  difcrences  in  retinal  elements.  As 
in  almost  all  of  the  sub-cla.sses  of  vertebrates 
there  are  differences  in  the  retinae  of  Birds' 
especially  in  the  tissues  of  the  rods  and  cones.' 
The  numerical  proportion  of  rods  to  cones 
in  different  species  is  quite  marked.  Uichest 
in  cones  are  the  diurnal  Birds  of  Prey  Cor- 
responding to  these  in  xNight  Owls  are  "rod- 
retmae."  M.  Schultze  thinks  that  while 
Owls  have  many  long  rods,  they  have  few 
cones;  Krause  believes  that  the  cones  are 
invisible  on  ccount  of  the  number  and  length 
of  the  rods,  but  that  they  are  no  less  numer- 
ous in  the  Owl  than  in  the  Falcon. 

(Jeese  have,   according  to  Krause,  many 
long  rods  and  stand  in  that  respect  mi.lwav 
between    Owls   and   diurnal    Birds   of   Prey 
The  Flamingo  has  the  longest  of  all  rod  ex- 
tremities.   The  Heron  has  manv  thick  rods 
Krause  seeks  to  weaken   the  force  of  the 
statement  of  .Schultze,  that  Nocturnal  Birds 
are   distinguished    by   the   preponderance   of 
cones  and  a  diminished  number  of  rods    bv 
pointing  to  the  discovery  of  Ileinemann  Ih'^' 
in  (the  nocturnal)  Xycticorax  the  rods  are 
scarce;  that  the  Swallows.  Ilirundo  rustiea 
and  Chehdon  urbica,  in  the  relative  increase 
of    their    cones    resemble    the    Owls,    while 
Athena  noctua  possesses  even  more  cones  than 


THE  FUNDUS  OCULI  OF  BIRDS 


rods.  According  to  Hess,  the  number  of 
cones  ,n  the  OwPs  retina  reaches  1  to  i\ ', 
millions. 

However  the  teaching  of  Schultze  has  much 
in  Its  favor;  insofar  as  that  the  hypothesis 
supported  by  it,  viz.,  that  ccnes  are  reallv 
CO  or-pereipient  organs  (the  rods  perceiving 
light  and  form)  finds  proof  in  the  fact  that 
rods  alone  are  found  only  in  the  retinae  of 
<ieep-sea  Fishes  and  Whales. 

Hegarding  the  possession  of  retin,  I  „// 
droplets,  ellipsoids,  paraboloids  and  hyper- 
bolo,ds,  there  are,  accor.ling  to  Krau.se,  manv 
«lilferences  in  siiecies.  In  Cardinalis  rirgin- 
umus  and  Fnngilla  spinas,  he  differentii'itcd 
two  kinds  of  cones;  in  the  Hen  three  outer 
double  cones.  Fringilla  spinns  shows  a  bine 
oil  droplet  in  many  of  its  double  cones. 

The  layer  of  nerve  filaments  receives  in  tlu- 
ligeon  and  a  few  other  birds  partly  medul- 
lated  fibres.  Franz  finds  in  manv  birds  that 
the  layer  of  nerve  filaments  in 'the  vicinitv 
of  the  optic  foramen  corresponds  to  what  ili 
•Mammals  are  called  "spider  cells." 

Pigment  Movement  in  the  Retina  of  Birds 
Although  this  strange  phenomenon  probablv 
occurs  m  most  vertebrates,  and  to  a  slight 
extent  m  some  invertebrates,  yet  it  is  in  birds 
that  It  IS  best  studied.  As  Kalt  remarks,  the 
retmal  pigmented  epithelium  forms  fringes 
which,  under  the  influence  of  light,  descend 
to  the  external  hraiting  membrane.  In  the 
dark  they  do  not  move  past  (at  least  in  the 
I  igeon)  the  middle  of  the  rods  and  cones. 

Th  purple  of  the  retina  is  missing,  accord- 
mg  to  Kuhno,  from  the  rods  ...d  cones  of  the 
Hen  :  nd  Pi^ron.  It  exists  in  large  quantities, 
howe^or,  m  the  external  segments  of  the  rods 
of  the  Scrwch  Owl,  while  the  cones  are  devoid 
of  it. 

As  Kuhne  points  out,  the  cones  have  vari- 
able dimensions,  and  are  single  or  double 
At  the  end  of  the  internal  segment  they  have 
a  single,  oily,  colored  ball  or  droplet,  which 
however,  is  not  found  in  the  interior  of  thJ 
accessory  cones.  In  a  fresh  retina  the  bulls 
show  immediately  with  their  various  tints 

As  far  as  the  color  of  the  retinal  oil-droplet 
of  Birds  m  general   is  concerned,   Schultze 


ANATOMY  OF  THE  FUNDUS  ORGANS   IN  BIRDS 


differentiates  mainly  (a)  colorless,  (6)  yellow 
to  reddish-yeilow  and  (c)  red  droplets. 
Again,  Le  finds  a  difleronce  between  Day 
Birds  and  Owls  in  that  the  red  are  lacking 
in  the  latter  while  the  pale  yellow  and  color- 
less varieties  are  more  plentiful. 

According  to  Kalt,  Waelchli  distinguishes 
four  varieties  of  colored  oil  drojilets  in  the 
avian  retina;  red  halls  disseminated  over  the 
whole  membrane;  orange,  or  yellow  balls, 
whose  distribution  is  the  same;  greenish- 
yellow  ones  seen  at  the  periphery;  and  un- 
colored  ones  spread  in  small  f|uanlities  over 
all.  Osmic  acid  colors  all  the,e  balls  black. 
The  coloration  is  particularly  intense  in  the 
macular  region. 

The  locality  in  which  the  colored  droplets 
are  found  varies  with  each  tint.  The  green 
balls  are  situated  nearest  the  external  sur- 
face of  the  retina,  the  red  come  next,  then 
the  yellow,  and  finally  the  colorless  balls. 

A  chemical  examination  of  the  colored 
glol)nles  in  the  cones  of  birds  was  made  by 
Kuhne.  A  hundred  retinas  of  the  Hen  were 
treated  with  alcohol  and  ellier.  The  fatty 
material  thus  dissolved  (colored  re<l)  gave, 
with  soda,  a  soap  from  which  was  extracted 
by  petroleum  ether  a  green  coloring  matter; 
iiy  sulphuric  ether  an  orange  material;  by 
turpentine  a  deep  rose  colorant;  this  last' one 
is,  however,  insoluble  in  sulphide  of  carbon. 
Kiihne  gave  the  names  of  chloroplianc,  xanlh- 
ophaiic  and  rhodopkane  to  these  pigments. 

The  Amt.1  of  the  Kdina  in  Birds.  Avian 
areae  centrales  are  of  greater  variety  —  espe- 
cially regions  of  distinct  vision  —  and  in 
greater  number  than  in  other  Vertebrata>. 

As  described  (.see  Chapter  VH,  page  59)  and 
depicted  elsewhere  (Figs.  110  to  115  inclu- 
sive) the  writer  believes  that  there  are  at 
least  six  forms  of  these  area?  in  Birds. 

According  to  Chievilz  (1891)  and  Slonaker 
(1897)  there  is  at  least  one  round  macular 
region  with  a  fovea  in  practically  all  Birds. 
This  single  area  of  monocular  vision  (see 
Figs.  110  and  111)  is  in  most  Birds  situated 
somewhat  centrally,  slightly  to  the  temporal 
or  the  nasal  side. 

In  many  species,  diurnal  Birds  of  Prey  for 
example,  besides  a  central  fovea  in  the  nasal 


19 

aspect  of  the  retina,  fovea  nasalis,  there  is  a 
fovea  temporalis,  which  with  the  fovea  tempo- 
ralis of  the  opposite  eye  may  serve  for  binocu- 
lar vision. 

The  area  centralis  retina:,  macula  liitea  or 
macular  region,  is  found  in  all  classes  of 
Vertebrates  and  its  presence  is  the  rule,  espe- 
cially 111  Reptiles  and  Birds. 

The  terms  commonly  applied  to  the  various 
parts  of  the  macular  region  are  as  follows: 
the  whole  area  is  designated  the  macula,  or 
area   centralis  or   "yellow   spot;"    the   more 
•sensitive,  smaller  area,  generally  disposed  in 
the  geometrical  center  of  the  macula,  is  called 
the  fovea.     Not  infrequently  there  is  .seen  a 
still  .-mailer  point  at  the  bottom  of  the  foveal 
depression;  this  is  termed  ihcfoveola.     This  is 
the  terminology  employed  in  human  ophthal- 
mology and  there  seems  no  good  reason  why  it 
should  not  be  applied  to  all  vertebrate  eves. 
When  the  macula  is  placed  on  the  nasal 
aspect  of  tlu!  optic  entrance  it  is  called  the 
naml  macula  or  area  na.«ali.f;  on  the  temporal 
side,  the  temporal  macula  or  area  temporalis. 
In  the  same  way,  one  speaks  of  the  area  or 
fovea   na.'iali.f   and  fovea   temporalis. 

The  area  centralis  presents  a  thick  portion 
of  the  retina,  where  the  arrangement  of  the 
elements  recalls  that  observed  at  the  level 
of  the  "yellow  spot"  of  the  human  retina. 
There  is  in  this  region  an  increase  of  gan- 
glionic cells  and  of  the  receiving  or  percipient 
elements  —  the  cones  and  rods. 

The  depth  of  the  fovea  may  be  regarded  as  a 
mea.sure  of  the  sharpness  of  vision.  Slonaker 
classifies  fovea;  as  deep,  medium  and  shallow. 
The  round  fovea  is  especially  "deeji"  in 
swift  Fliers  and  Birds  of  Prey;  "medium"  to 
"weak"  in  most  other  birds,  except  that  it  is 
"shallow"  in  the  domestic  Pigeon,  and  prob- 
ably lacking  in  the  Hen. 

Krause  is  probably  right  in  believing  that 
domestication  brings  about  the  disappear- 
ance of  the  fovea. 

Both  fovea'  in  the  bimacular  fundi  of  diur- 
nal Birds  of  Prey  are  structurally  much  alike, 
ill  that  they  have  in  them  only  cones,  and  only 
those  with  yellow  droplets. 

Besides  this  central  area  (with  a  fovea) 
there  is  often,  in  Birds,  a  ribbon-  or  band-like 


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THE  FUNDUS  OCULI  OF  BIRDS 


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ANATOMY  OF  THE  FUNDUS  ORGANS  IN  BIRDS 


arrdngement  of  retinal  lismie  tliat  is  ffcnerally 
foiiiul  ill  the  horizoiiliil  inoridiiiii.  It  is  mostly 
soi-ii  ill  tiiosc  l)ir(ls  that  seek  Ihcir  food  ujmn 
the  ground,  c.k..  Moto.iNa.  Saxicoia,  Stnithio, 
Totamis.  Triii«a,  Lams,  Squatarola;  also 
III  Iho  (ioosc,  Mainiiigo  and  otlier  A(|uatic 
Itirds.     Sec,  for  example.  Figure  11. 

Perhaps  tJie  retina  manifests  the  greatest 
foveal  development  in  swift-flyiiiK  Iiirrls.  For 
example,  Cypselas,  Ilirundo  and  Sterna  have 
three  fovea'. 

Sioiiaker  has  also  noticed  an  important 
variation  in  the  relative  position  of  avian 
fovea'  and  has  offered  an  explanation  home 
out  l)y  the  resnits  of  this  investigation;  the 
fovea  nasalis  is  almost  invariably  found  in 
the  same  fundus  area,  Imt  the  locality  of  the 
toniTioral  fovea  de|)ends  upon  the  position  of 
the  e  in  the  head.  As  the  eyes  arc  turned 
more  and  more  forward  the  fovea  temporalis 
approaches  the  fovea  na.salis.  As  binocular 
vision  become.s  more  frecjuent  both  foveie 
may  become  merged  into  one,  generally 
deeper,  i)it.  There  is  also  a  corresponding 
change  to  an  asymmetrical  form  of  the  eye- 
ball and  to  a  peculiar  position  of  the  crystal- 
line lens  in  birds  with  binocular  vision. 

In  many  such  birds,  the  White-bellied 
Swallow  (see  Fig.  ii)  and  the  various  Terns 
for  example,  the  nasal  fovea  is  deep  and  sharp, 
while  the  temporal  fovea  is  quite  shallow  and 
the  eyes  are  almost  symmetrical:  but  in  birds 
with  more  marked  binocular  vision.  Hawks, 
for  example,  the  temiioral  fovea  has  the 
greater  depth  an<l  the  eye  becomes  more  asyni- 
melrical.  Tlu'  climax  is  reached  in  Owls, 
whose  eyes  are  most  irregular  in  form,  who 
have  but  one  (deep)  temi)oral  macula  and 
who  se<'  only  binoeularly. 

.Vs  with  other  organs  in  their  body  the  com- 
|)oncnl  parts  of  the  visual  apparatus  of  Birds 
arc  arranged  and  adjusted  mainly  to  enable 
the  Bird  lo  obtain  food  ancl  to  escape  his 
hereditary  enemies.  In  a  minor  degree,  too, 
we  observe  the  inlluence  of  the  necessity  for 
swift  locomotion.  Otlier  (occasional)  taxo- 
noinic  influences  are  apparent  in  certain  special 
visual  rerinirements,  such  as  nocturnal  vision, 
the  use  of  the  eyes  under  wi.ter,  the  employ- 
ment of  the  eyes  for  vision  both  in  air  and 


21 

water,  the  visualization  of  minute  objects 
close  at  hand,  etc.  This  statement  is  true 
in  full  measiin-  of  the  organs  and  tissues  com- 
prising the  fundus  oculi. 

Stereoscopic,  binocular,  single  vision  in 
Birds  with  double  foveie  —  and  this  is  the 
most  acut<,  accurate  and  effective  form  of 
eyesight  that  these  or  any  other  animals 
know  —  is  probably  accomplished  by  the  two 
temporal  foveie  acting  in  cerebral  uni.son. 
It  is  this  form  of  sight,  for  example,  that 
enables  the  Osprey  and  other  Hawks  first  to 
locate  from  a  distance  and  then  to  dart 
unerringly  upon  their  prey. 

The  deep  and  evidently  more  acutely  func- 
tionating nasal  fovea  is.  in  the  writer's  opin- 
ion, employed  for  monocular  vision  only, 
and  there  seems  every  reason  to  believe  that 
Birds  with  double  fovea?  have  exceptionally 
good  eyesight  with  each  eye  .se|)arately;  they 
are,  liy  this  effective  combination,  enabled 
not  only  to  command  a  view  of  the  highest 
efhciency  over  the  whole  horizon,  but  also  have 
the  power  to  concentrate  it  when  needed  upon 
particular  objects  invisible  or  indistinctly 
visible  to  other  species  not  so  provided. 

It  must,  however,  be  acknowledged  that 
the  neurology  of  Birds,  involved  in  these 
questions,  is  a  sub-.seetion  of  biology  as  yet 
in  its  infancy;  only  when  the  histology, 
pathology  and  experimental  physiology-  of  the 
avian  cerebrd  organs  and  their  connections 
have  been  w.  :ed  out  as  they  have  been  in 
Man  sliall  we  know  how  the  paths  pursued 
by  "brain  eurrents"  involved  in  this  switch- 
ing from  monocular  single  vision  to  binocular 
siglit  run  and  are  controlled.  As  these  ques- 
tions now  stand  the  om,,  certain  thing  that 
can  be  said  is  that,  with  the  po.ssible  exception 
of  the  Owls,  they  must  be  totally  unlike  the 
cerebral  and  spinal  arrangements  discovered 
in  Man  and  the  higher  Apes. 

Of  the  irfiysiologj-  and  psychology  involved 
in  the  ribbon-  or  band-like  area  we  know  still 
less.  In  all  probability  it  is  a  device  to  enable 
swift-flying  birds  to  take  their  prey  on  the 
wing,  and  other  species  to  find  their  food  on  the 
ground  while  they  themselves  also  stand  on 
terra  firma;  in  other  words,  birds  with  banded 
retinae  possess  eyes  that  are  chieflj-  employed 


T^WM^ 


22 


THE  FUNDUS  OCULI  OF  BIRDS 


in  food-searching  in  such  u  fashion  that  ♦hey 
are  enal.le.l  to  see  one  object  very  distinctly 
iiNd  neighboring  objects  (in  a  restricted  field 
of  vision)  more  distinctly  than  is  permitted 
l>y  the  comparatively  insensitive  retina  of 
the  roniaininj;  fundal  areas. 

IiifulaiHiiullary  angle.  The  relations,  es- 
JKcially  of  fundal  position,  between  the  optic 
nerve  entrance,  the  pecten,  and  the  areas  of 
distmct  vision  are,  as  we  have  nireadv  seen, 
of  some  biological  importance.  I'pon  the 
locality  of  the  macular  regions  depend,  in 
great  measure,  the  qualify  and  precision  of 
the  eyesight  o.  each  particular  bird.  That 
one  may  facilitate  references  to  the  location 
in  the  eyegrou'id  of  the  retinal  band  the  writer 
proposes  to  measure  what  he  has  lerme.l  the 
nifulapapillary  angle  {in/ula,  a  band,  papilla, 
the  optic  <lisc),  made  by  the  junction  of  the 
major  axis  of  the  ovoid  eiitrnnte  of  the  optic 
nerve  prolonged  until  it  meets  the  retinal 
band  on  the  nasal  side  of  the  point  of  contact. 
In  the  case  of  the  Hudsonian  Curlew  (see 
Fig.  125)  it  is  50°. 

The  Optic  Nerve  of  Birds 
In  all  Vertebrates  the  oi)tic  nerve  has  the 
form  of  a  cord,  sometimes  very  short,  as  in 
Birds,  and  occasionally  long,  as  in  Man. 
which  extends  from  the  optic  foramen  to  the 
posterior  segment  of  the  eyeball,  where  its 
expansion  forms  the  retina. 

In  Birds,  whose  ocular  movements  displace 
the  eyeball  very  little,  the  nerve  takes  the 
form  of  a  short,  almost  rectilinear  cord;  while 
in  animals  with  mobile  eyes,  such  as  the  large 
Mamnufers,  the  nerve  is  long,  round  and 
b-sha{)ed,  to  follow  the  displacements  of  the 
posterior  hemisphere  without  pulling  or  drag- 
ging. Its  diameter  greatly  varies;  it  may 
reach  8  mm.,  as  in  the  Whale.  The  rule  is 
that  it  roughly  corresponds  in  size  and  length 
to  the  volume  of  the  eye-ball. 

As  Kalt  says,  the  pia  mater  forms  the 
neurilemma  or  sheath  of  the  optic  nerve. 
Ihe  multiple  partitions  which  it  sends  into 
Its  substance,  divide  the  nerve  into  bundles; 
tlie  dissepiments  anastomose  with  each  other' 
Tins  is  the  type  well  known  among  Mammals. 
Birds  exhibit  one  peculiarity;  at  the  inner 


aspect  of  the  nerve  the  pial  partitions  pene- 
trate perpendicularly  into  the  substance  of 
the  nerve  and  do  not  ana.stoniose  until  they 
reach  about  half  way  into  the  thickness  o'f 
the  cord.  Analogous  jK-rpendicular  parti- 
tions, but  very  short,  exist  .sometimes  on  the 
external  side.  The  result  is  that  the  nerve 
has  a  foliated  appearance,  especially  marked 
on  the  internal  side. 

The  Pecten,  Marsupium,  Fan  or  Comb 

of  Birds 
By  means  of  the  ophthalino.seope  and  direct 
illumination  there  is  seen,  below  and  exter- 
nally, in  the  fundus  of  every  bird,  a  black 
mass  of  variable  form.  When  the  free  edge 
of  this  organ  is  illuminated  one  notices  a 
longitudinal  strip  with  undulating  e.'ges. 
If  one  throws  the  light  upon  the  base  of  this 
object  — the  pecten  or  comb  —  the  papilla 
looks  like  a  sparkling  white  area  whose  mar- 
gins are  ed<red  with  black,  the  center  being 
occupied  by  the  irregular,  black  mass. 


Fig.  13 

Diagram  Showing  the  Relations  of  the  Optic  Verve 
Entrance  to  the  Pecten  and  the  Basilar  Artery  and 
Vein  in  the  Sparrow.  (Wood  and  Slonaker.")  4 
artery  to  pecten,  which  sends  a  branch  along  each  fold' 
ch  choroid;  on,  optic  nerve;  peet,  pecten;  ret,  retina- 
ire/,  sclerotic;  r,  vein  fro-i  pecten,  which  receives  a 
branch  from  each  angle  oi  the  folds. 


:-JMii-t  ' 


ANATOMY  OF  THE  FUNDUS  ORGANS  IN  BIRDS 


The  pectinate  image  seems  to  be  displaced 
by  abrupt  iiiovenients  in  the  vitreous  mass, 
disturbances  due  probub'y  to  contractions  of 
the  ocular  muscles,  external  and  internal. 

As  Kalt  says,  the  pecten  is  a  membranous 
organ  covered  by  a  black  pigment  attache<l  to 
the  optic  nerve  and  projecting  a  variable 
distance  into  the  vitreous  body.  This  organ, 
studied  and  described  for  the  first  time  by 
Perrault,  in  1876,  received  later  the  name 
comb  ipcigne).  The  tern,  "comb"  is  not 
exact  since  there  are  no  stparute  teeth;  per- 
haps "fan"  better  describes  the  appearance 
of  this  organ.  German  authors  still  call  it 
the  "fan"  (Faclier). 

Except  in  the  Ostrich,  where  it  has  the  form 
of  a  cone  inserted  into  the  optic  nerve  and 
<livided  into  two  parts  by  a  sort  of  white 
partition,  the  pecten  represents  a  triangular 
or  rectangular  pigmented  lamina,  whose  plane 
is  directed  down  and  out. 

Generally  it  does  not  extend  into  the 
vitreous  beyond  the  intercalary  zone  of  the 
sclerotic,  and  it  is  only  exceptionally,  as  in 
the  Goose,  the  Swan,  the  Stork,  etc.,  that  it 
reaches  the  crystalline  lens.  The  comb  is 
made  up  of  a  lamina  folded  upon  itself  and 
producing,  in  a  transverse  section,  a  markedly 
zig-zag  effect.  The  nund>er  of  plications  varies 
from  5  to  30,  averaging  16,  as  in  birds  of  prey 
ami  Gallinacea;.  The  writer  and  Slonaker 
counted  18  folds  in  the  English  Sparrow. 

Among  the  Owls,  the  length  of  the  comb  i- 
J  mm.  >it  the  base;  its  height,  4  mm.  In  the 
Stork  the  base  is  1^  mm.  long;  it  is  7  mm.  high. 
Kalt  believes  the  pecten  to  be  essentially  a 
vascular  organ.  It  is  composed  of  a  network 
of  capillary  vessels  of  unequal  d-'niensions 
spread  out  in  two  or  three  superimposed 
planes,  whose  mesh  ni.iy  vary  in  form  and 
dimensions.  In  the  Goose  the  vessels  are 
nearly  all  parallel;  the  anastomoses  are  rather 
rare  and  the  meshes  actiuire  great  length. 
The  thin  connective  tissue,  which  serves  as  a 
support,  contains  free  pigmt  it.  The  entire 
organ  is  enclosed  in  an  envelope  of  endo- 
thelium. 

Kalt  further  thinks  that  the  pectinate 
blood-snnply  is  derived  from  the  external 
bran'  he  internal  car  .i.!   which,  imme- 


98 

diately  after  leaving  the  temporal,  forms  a 
large  plexus.  The  branches  from  this  plexus 
cross  the  sclerotic  and  re-unite  in  a  single 
trunk,  which  corresponds  to  the  central  ar- 
tery of  the  retina  in  mammifers.  This  trunk 
extends  to  the  base  of  the  comb,  where  it 
gives  off  several  ascending  vessels,  that  iK'iie- 
trate  the  latter  and  form  a  large  capillary 
plexus.  The  venous  Ijlood  is  relurned  by  a 
large  choroidal  vein  which  perforates  Hie 
sclerotic  a  short  distance  towards  the  middle 
of  the  comb.  Note,  also,  that  it  makes  at 
the  level  of  the  ocular  groove  several  variaiile 
anastomoses  with  the  plexus  of  posterior 
ciliary  arteries.     See  Figure  13. 

According  to  Beauregarde  the  pecten  is 
allied  to  the  choroid;  it  appears  after  the 
fourth  (lay  in  the  embryo  of  I  lie  Hen. 

The  fiiiirtioii  of  th"  pectni  has  from  lime 
to  time  been  variously  interpreted.  It  has 
been  considered  particularly  as  an  erectile 
organ  capable  of  displacing  the  crysti.. 
lens  and  thus  taking  part  in  the  accomuK 
dation  of  the  eye.  Beauregarde,  using  the 
ophthalmoscope,  found  displacements  of  the 
organ  and  rapid  vibrations  synchronous  with 
the  movements  of  the  nictitating  membrane. 
But  he  noticed,  above  all,  that  the  comb  is 
placed  so  as  to  intercept  the  rays  coming 
from  the  front  and  from  above;  that  is  to  say. 
those  rays  that  reach  the  two  eyes  simulta- 
neously. In  catching  them,  the  pecten  is 
supposed  to  suppress  momentarily,  in  this 
way,  I)iiiocular  vision,  a  condition  which  is 
necessary  for  the  more  perfect  use  of  monocu- 
lar vision. 

No  (loul)t  the  pecten  occasionally  serves  as 
a  scrcer  to  protect  t.he  retina  against  the  rays 
of  the  sun.  Observation  of  the  attitude  of 
the  lien's  head,  when  exposed  to  the  sun,  is 
favorable  to  this  supposition,  as,  also,  the 
slight  development  of  this  organ  among 
nocturnal  birds. 

Another  hyp  .thesis,  which  seems  plausible, 
attributes  to  the  comb  the  role  of  an  organ  of 
nutrition  for  the  vitreous,  and  makes  of  it  an 
appendage  of  the  ciliarj-  body.  It  has  al.so 
been  suggested  that  it  is  an  organ  of  excre- 
tion, charged  with  maintaining  the  intraocular 
tension. 


'liMrm  t}9WiHn&»«fcPK7.W2Mi*  ;urf:l.-s: 


n 


Friiiiz  tl,)os  not  Ik-IiVv..  tlu.t  tlic  fii„.  stnic- 
l>ir..  „f  fh.-  I,ir,r.  iMTt.-n  has,  as  y.-t.  Ihh-.i  fullv 
'l<-«r,l.,.,|.  The  striKt.iral  arradKi-ment  il. 
Nn.lhio  shows  it  to  ho  .lifforenf  from  othvr 
>ir.ls.  ,vl„.,v  It  ,s,,ri„Ks  as  a  sort  of  wriiiklr.l 
'•■Mf  from  Ih,.  paj.ilh.  an.i  has  an  vuhr^vun-ut . 
wlu.'h  K-  tmns  th,-  •■I.ri,l«,.."  which  n.ns 
^'lo'iK  th.-  .-ntirc  margin  of  H„-  ,,,h(,.i,.  S,.<- 
liKurr  n  an.l  I'h.i,.  I.  The  fohls  are 
«rl,|,..l  toK,.|hor  l.y  this  l.ridg,-.  so  that  thov 
<an  only  Im.  smooth.',!  out  l.y  ruttinK  awav 
thf  la  t  tor. 

Til.'  liixMofiiral  xtnwiure  of  the  liird-x  ,rctc„ 
has  l.o,.„  inv.'.stiKat.'.!  I.y  Mihalkowics.  D.-ms- 
s.'nko.  Born.!  an.l  others.  H.'rn.l  .iaims  that 
the  IK-  ten  is  not  primarily  of  m.'s.j.j.'rmal 
oriKin  an.l  an  ap,,,.n,lix  ..f  the  .horoi.l.  as  was 
fornu-rly  hehl  (In  Kessler,  for  instance),  l.ut 
IS  really  a  .lerixative  of  the  retina  or  of  the 
<)|)tie  nerve;  in  sh.irt.  an  otFshoot  of  th.> 
eentral  nervous  sysl.'ni  an.l,  eon.s.'onentlv 
of  Ih.' eeto.lerm. 

Franz  maintains  that  the  p.'et.'n  is  a  s.-nse 
organ,  assisting  in  the  regulation  of  the  intra- 
oenlar  pressure  an.l  the  act  of  a.'eonimo.la- 
l'">>.     On   the  np,„'r  .snrfa.'e  of  the  p.'ct,.n 

Ihat   is  <m   the   "l.ri.lg..,"  Franz  f .|   fi|,,- 

I'lenls  that  eii.l  th.-re  in  elul.-shap.M.  „o.hVs 
sirueturally  l..'tw,-en  ,.igmenl.'.l  nu.l.'i  a:i.l 
'ell  -uielei,  .in.l  h,'  believes  we  may  look  up.m 
t!:.'  pecten  primarily  as  a  glia-stru.tiire,  an 
'.pin.on  also  hehl  by  nickniann  an.l  v 
H..s,.n.  .^till.  Franz  will  not  say.  nor  ,1,„.' 
JJIockn.ann,  that  ther.'  is  to  be  foun.l  in  the 
pt'oten  any  convinring  .'vi.ienoe  of  th.-  pres- 
ence of  true  nerve  filani.'nts. 

Franz  an.l  Ilushke  point  .n.t  that  the  pect.-n 
IS  all  the  more  dovel..i,e.l  the  nior.-  th.'  bir.l 
makes  u.se  of  monocular,  an.i  less  of  binocular 
vision;  that  the  pecten  of  Song-bir.ls  is  larg.- 
an.l  rich  in  wave-like  fol.ls,  while  the  much 
faster  flying  Swallow,  with  b.'tt.'r  a.'cm- 
ino.lation.  has  a  more  poorly  .l.-veloiM'-l  pe,- 
ten.  The  Owls,  also,  with  their  small  in-cten 
nave  binocular  fi.\ati.)n. 

Both  in  Birds  and  Reptiles  th.T.'  is  a  close 
lonnecti.m  between  the  pecten  and  the  -■  c- 
oiis;  111  other  words  between  that  organ  and 
the  margins  of  the  hyaloid  .'anal,  or  slit,  in 
which  it  IS,  as  it  were,  inserted. 


THE   FUNDUS  OCULI  OF  BIRDS 


Franz  d.H-s  not  f,>el  certain  about  the  vas- 
euhir  supply  .,f  the  pecten  of  ihe  Bird  Uv 
I'eliev.'s,  iiowever,  that  the  bloo<lv..ssei  that 
rnns  along  the  base  of  the  ,H-cten  giv.-.s  off 
bran.'hes  to  the  folds  las  shown  in  Fig  I.-)) 
ami.  to  a  less  extent,  t..  Ilie  |X'.'tinate  t.ri.lge. 
Ilie  main  vess.'l  is  to  be  r.'gar.led  as  the 
artery  (atferent  vessel)  .,f  the  pecten 

We  find  glia-growths  like  lii.,s.'  of  the  avian 
pecten  .'inanating  from  the  papilla  in  many 
Mammals  and  which  pr.'stnt  the  same  char- 
a.t.-rs  as  thes,'  organs  in  Reptiles.  In  the 
ey,'  of  Anij)hibians  and  Fisiies  tlierc  are  no 
such  glia-growths. 

After  many  .iissections  and  much  considera- 
tion ..f  th..  finer  anatomy  of  th.'  ..rgan  Slonak.'r 
aiKi  the  writ.'r  .lo  n..t  r.-gar.i  the  avian  pect.'ii 
as  anything  more  tlian  a  s.'ri.-s  of  blo.jdves.sels 
«itli  a  deeply  i)igmente.l  framework  ..f  gha 
hbre..:  and  ceils.     So  far  we  have  been  unable 
to  find   in   numer.)us  serial  .sections  of  the 
Sparrow  s  iK'cten  (or  in  that  of  anv  otlier  bird 
so  far  examiiu.l  by  us)  d.'finite  ciliated  struc- 
tures, sensory  bu.ls.  .,r  any  other  app..ar«nce 
t  lat   would  justify  a   l,..|i.'f  oth.'r  tlian  that 
this  organ.  deei)ly  pigment.'d  to  absorb  tlie 
liKht  rays,  has  any  fun.ti.,n  a|)art  from  tiiat 
of  a  earner  ..f  nutritive  pabulum,  chi.-Hv  to 
the  vitrous  an.l  ant.'rior  lay.-rs  of  tiu-  retina 
It  may  cliang.-  its  jjosition,  a.tual  or  n-lativ.- 
during  acommodathm,  but  it  has  no  ..Ihcr 
e..nnection    witli    the    accomm.Kiative    act 
Tiie  covering  of  all  its  fan-like  f.jlds  is  e.,n- 
tmuous  and  i.lentical  with  the  hvahiid  nieni- 
bran..  or  menibrana  limitans  of  tiie  retina 
"e  di.l  not  find  in  the  Sparr.)w  .inv  anasto- 
nioses  between  the  vessels  .,f  the  p-'-cten  and 
t he  other  ..cular  structures.     The  branch  .)f 
the  o|)hliialmic  artery  that  enters  the  eye- 
l>all  .'hwe  to  the  optic  nerv.-  sh.'ath  (to  pe'ne- 
trat.>  the  huter  at  the  plane  of  the  .sclerotic 
coal)  IS  tlie  ..nly  afferent  ves.sel-suppiv  of  the 
pecten   that    w.-   were   able   to   .lemonstrate 
eith.T  by  gr.Kss  .iis.section  or  in  serial  micro- 
scopic .sections  .jf  this  region. 

In  the  .same  way  there  apfwars  to  be  onlv 
one  efferent  vein  which  may,  iiowev.'r,  liave 
r.-c.'ived  oth.'r  venules  bef.)re  its  exit  from  th,' 
globe,  .several  millimeters  distant.  These  two 
latter  observations  are,  however,  based  on  an 


i«Ti»"BiT-»jL^' 


AXATOMV  OF  TFIE   FUXDIS  ORGANS   I\   BIRDS 


inconiplftc  (lisvclion  of  llic  purls  hikI  may 
hv  iiiii(!ifi<'<|  lattT. 

]t\  lliis  ju(l«niriit,  if  we  rcjiil  liini  iiri)jlil. 
Tn-ncliiT  Collins,  to  somr  cxlcnt,  concurs. 
In  liis  Krasniiis  Wilson  Lectures  on  the  \nal- 
oni.v  an<l  I'atliolojry  of  the  Kvc  lie  remarks 
lli.il  "in  other  animals  than  Mammals  and 
in  tlie  human  fetal  eye  there  are  sources  of 
nutrient  supply  to  the  intraocular  structures 
in  place  of  or  in  acMition  to  the  ciliary  Ixxly."' 
He  adds  that  the  pigmented,  plicated  strnc- 
liir<'  of  the  bird's  jM-cten  '•closely  resemlih-s 
the  ehoroiilal  coat  .  ,  having,  how.'vcr, 
a  rather  finer  capillary  plexus.  Minis,  there- 
fore, not  only  possess  well-formed  ciliary  pro- 
cesses hut  also  ;i  special  vascular  arran},'emcnt 
ill  the  vitreous  ciiamlicr." 

AccordiiiK  to  O.  Zietzschmann.  also,  the  pec- 
ten  is  covered  hy  a  delicate  meml)rane  which 
is    continuous    with     the    inner 
limilinfj  memlirane  of  the  retin.i. 
The   Moodvcssels.   accordinj-    to 
him.  Iielon;;  to  the  ciliary   sys- 
teui  and  are  hrauches  of  those 
supi)lied    to     the    optic     nerv<>. 
Leher  l)elic\es  the  pectin.ile  .o- 
tery  to  lie  (he  li<imolo^'ue  of  the 
li>aloid  artery. 

Finally,  it  may  ix-  added  that 
there  arc  n.)  '.iood vessels  in  the 
Hinls'  retina  and  the  vessels  of 
the  |>eclen  do  not.  conse(|uenliy. 
arise  from  a  central  artery  of 
the  oj)tic  nerve  as  in  Mammals 
since  tliat,  too,  is  wauling;. 

This  arratifiement.  inasnnieh 
as  the  (ipa(|ue  vessels  tlo  not. 
as  in  most  Mammals  and  other 
Vcrt(l)rata',  interce{)t  the  rays 
of  lifjhf  impinginf;  on  tlie  per- 
cipient elements  of  the  retina,  makes  for  a 
mon-  distinct  and  measurahly  clearer-cut 
iniaj,'e  of  the  ohject  visualized  hy  the  avian 
brain. 

Compamlirc  ophthahnoscopii  of  reptUiaii 
fundi.  With  the  aid  of  Mr.  Ilea.l's  brush  and 
by  courtesy  of  Dr.  Linds;.y  Johnson  the  writer 
is  .-djlc  to  compare  a  few  typical  fundi  of 
Rejjtiles  with  those  of  their  ancestral  cousins 
the  Birds. 


85 

It  re<iuires  only  a  glance  at  these  pictures 
to  feel  assured  that  the  eyes  of  that  nocturnal 
replih-  tlie  Turkish  (ie.ko  il'hit.'  LIX). 
whatever  els.-  may  be  said  on  the  subject, 
are  more  decidedly  avian  or.  rather,  more 
ornithosaurian  than  are  those  of  the  Horned 
Toad  (Plate  lAi.  or  Indian  Coljra  i  Plate 
lAI),  whose  fundi  belong  more  distinctly  to 
other  vertebrate  types.  These  last-named 
possess  definite  retinal  vessels  (that  issue 
from  a  circular  optic  i)apilla),  an.l  they  have 
no  pecten  or  at  h-ast  th<'  mere  suf,'i;<'slion  of 
one.  (•om])are  Plate  lAI  with  Fij;.  14;j; 
and  l'lat(  lA  with  Fi^.  I  U,  which  sli.os' 
the  nsembhince  betw<>en  the  Cobra  fundus 
and  that  of  the  Hed«e-IIof;.  while  the  eye- 
ground  of  the  Horned  Toad  sunfjcsts  tl  it 
of  the  Virginian  Opossum.  For  further  com- 
parison   a   diaKrani    of   an   ichtliyan   fundus 


Fig.  14 

OpbtlialinosTOpic  \-ie«-  „f  Ur.  F.nulus  of  tlie  Fi>l.  <,a<l,u  merlaiujw, 
(After  IWuregarde.)  Tlie  proeessus  faleiforinis  .l.liuk)  runs  ti.e  «liol,- 
length  of  the  (white!  optic  nerve-head,  at  the  iK-riphery  of  which  are  seen 
six  branelies  of  the  hyaloid  arterv. 


oculi  (Fij;.  14)  —  that  of  (iailiis  iiierhnKjim  ~ 
is  shown. 

If  one  may  draw  any  conclusion  from  such 
sparse  material  and  from  such  an  incidental 
examination  of  the  subject  it  is  that  whatever 
of  common  oripn  the  avian  and  reptilih.i 
clas.ses  may  have  originally  had  the  ornitho- 
logical branch  left  the  parent  stem  with  a 
subdivision  of  tlie  Lacertilia  and  not  with  the 
Ophidia. 


;r>»«r-.r.ir  VK'.t:j««K!"flE%i«:j£X'  v<tz:i!iK5sa3r.  -msii»'-iiu.:^^.tit  ns^"'!'. 


.  <r.-*ayK.  i.  •^««iBii«  far^JT 


ClIAITKU  V 

OF  THE  VERTEBRATE  EYE  BY  MEANS        ^^^ 
OF  THE  OPHTHALMOSCOPE 


Since  this  .sut.ject.  nlthouRh  fan.ili.r  f„ 
opht ha  nu.I.,gi.sts  (..ruli.ts),  is  rnn-lv  mnU-r- 
sto(Hl  l.y  naturalists  in  gen.Tal,  and  rsm- 
cmlly  not  h.v  ornithologists,  a  l.riof  rovi.-w  of 
ophthalmoscopy  us  practiced  on  the  verte- 
•rate  c-ye  may  not  l,e  out  of  place  in  a  work 
like  this. 

The  ancients  notice.!  that  the  eyes  of  some 
nninmls  are.  under  certain  conditions,  bril- 
liant in  twilight  or  .semi-darkness.     Although 
he  did  not  attempt  to  explain  the  phenon.e- 
non.  I  hny  remarks  that  the  eyes  of  animals 
that  see  at  night  -  cats,  for  example -are 
radiant  and  shining,  an.l   that  the  eyes  of 
the  she-goat  and  the  wolf  emit  a  light  like 
tire.    This  fact  continued  to  he  noted  through 
the  succcH-ding  centuries  and  was  commented 
on   more  or  less   by   other  obserxers.     Jean 
-Mery  of  1  ans,  who  in  1704  immersed  a  cat  in 
water,  beheld  in  all  its  glory  the  fundus  of 
that  animal  s  eye,  inclu.ling  the  opti<   nerve 
entrance,  the  retinal  bloo.l   ve.s.sels,  and  the 
remarkable  coloration  of  the  retina  and  cho- 
roid.    AKp.  did  not  giv  a  pro,,er  explana- 
tion of  this  phenomenon,  but  five  years  later 
<!<■  la  Hire  showed  that  the  refractive  power 
of  the  cornea  is  neutralized  by  immersion  of 
the  animal  s  eyes  in  water,  so  that  all  ravs  of 
liglit  reflected  from  a  given  point  of  the  fundus 
emerge  from  the  pupil  not  as  parallel  but  as 
divergent  ra.vs;  con.sequently  the  fundus  im- 
ages can  be  seen  as  if  one  were  looking  at  them 
in  the  dcpth.s  of  the  eye  through  air 

r  J^"  fj!"'*"^  °^""  <"■  Background  of  the 
Internal  Eye  in  Man.    Glimpses  of  the  human 

(26 


•HMilar  Ulterior  wer.-  oblained   from   time  to 
line  but  It  Wi,s  not  ,„,|il  the  year  1847,  when 

"Mbbage, an  E„,jli,h  mathematician, exhibited 
to  Wharton  .Jones,  a  well-known    oculist  <  f 
his   day,    the   model    of   an    instrument    by 
means  of  which  the  interior  of  the  eje  coul.l 
be    thoroughly    examine<l.     It    (consisted    of 
a  small,  plan.-,  glass  mirror  from  whose  centre 
a  portion  of  the  .silvering  ha,l  been  removed, 
i  ins   .levice  was  not  made  known  to  the  world 
until  1854.  iK-fore  which  date  the  cele»)rated 
phy.sicist,  Hermann  von  Helmholtz.pu'-.ished 
in  1851,  a  description  of  an  ophthalnK.scom' 
whu'l,  enables  the  observer  to  .see  with  eas.. 
all  the  parts  in  the  background  of  the  eye 

The  Ophthalmoscope.    The  original  Helm- 
holtz  instrument  consisted  of  four  thin  i)lates 
of  glass  carefully  polish,-d.  screwed  toj,etlier. 
fastened  at  an  angle  of  fifty-six  degrees  to  a 
t)rass  disk,  an.l  forming  the  hypothenus.-  .,f 
a  right-angle.:  triangular  prism.    Th.-  other 
si.les  of  this  hollow  prism  were  ma.le  of  metal 
an.l  all  carefully  l)lackened  inside.     The  brass 
•iisk  had  a  hole  in  its  centre  and  an  arrange- 
ment  to  ,)lace  a  concave   l.^ns   over   if   for 
n.)rmal  eyes  IWmhoItz  u.sed  a  \o.  10  (4  n  ) 
glass.     The  light  from  a  lamp  falling  on  the 
gass   plates   was  in   part  reflected   into   the 
observed    eye,    while    the    observer,    looking 
throu„'h  the  concave  lens  and  the  opening  in 
the  brass  disk,  received  the  returning  ravs  in 
his  own  eye,  and  was  able  to  see  the  fundus 
w(!akly  illuminated,  but  still  distinctly. 

The  instrument  now  in  use  for  examining 
the  interior  of  the  eye  more  ncarl        ,embles 


'•^A^^mju:. 


OPHTHALMOSCOPY  OF  THE   VERTEBRATE   EVE 


llic  ori>?iniil  nphtlmlriioscopf  of  HahlrnKf  lliHn 
lliiit  of  Hclnilioll/. 

It  consists  «s»<>ntially  of  a  coinavo  mirror 
of  ahoiil  «  (111,  fwiis  (inouiilfd  on  a  handle). 
with  u  small  (3  mm.)  hole  in  the  o-nft-r  and 
so  arranged  that  a  wries  of  eoneave  and  eon- 
vex  lenses  may  Ih-  presented  to  (he  (.peniiiR 
for  the  purpose  of  nentraliziiiK  tiie  refractive 
error  of  the  ol.server's  and  the  observed  <\e, 
thus  Riving  a  clear  view  of  the  fundus  details. 
There  are  numerous  opiithalnioscopie  niod- 
eU  in  the  market  today  -  iniproveinents  mi 
the  early  inventions  l.ut  the  iiistrunieiils 
of  F-orinK  and  Morton  are,  perhaps,  the  favor- 
ite forms  now  in  use.  Illustrations  of  Ihce 
are  ^iven  in  the  text.     S'e  Fijjs.  1.5  aixl  W. 

As  tlie  piirpone  of  an  ophlhalmoncupic  cx- 
aminalion  is  to  see  a.s  much  as  possilile  of 
the  interior  of  the  eye  under  observation  // 
is  (Imirnble  In  dilate  lite  pupil; -in  the  cas<' 
of  maniniai.s  'hi.s  is  aecomplislied  by  inslillin;; 
into  the  eye  afropin,  homatropin,  euphthal- 
niin  or  some  other  mydriatic. 

Before  the  invention  of  the  sflf-liimiiioiin 
or  eleclric  ophthalmoscope  (Fig.  «1)  the  source 
of  illumination  of  the  ocuhir  interior  was  a 
gas  jet  or  electric  bulb  —  preferably  an  nrgand 
lamp  —  stationed  in  a  darkened  room,  and 
placed  on  a  level  with  the  eye  to  the  side  of 
the  head. 

In  examinations  of  the  human  eye  the 
observer  sits  opposite  the  individual  whose 
ocular  interior  is  to  be  explored,  and  placing 
the  mirror  close  to  his  own  eye  and  about 
4()  or  r>0  cm.  from  the  eye  to  be  examined 
•^fleets  the  light  upon  the  latter,  while  he 
looks  at  it  through  the  small  opening  in  the 
ophthalmoscopic  mirror.  In  very  short- 
sighted and  very  long-sighted  eyes,  but  not 
in  normal  ones,  the  vessels  of  the  retina,  the 
entrance  of  the  optic  nerve,  etc.,  can  be  more 
or  less  distinctly  .seen. 

The  details  of  the  retina,  choroid,  etc.  (or 
fundus),  can  be  seen  in  two  different  ways. 
In  the  indirect  method,  as  applied  to  Man  and 
most  other  vertebrates,  the  observer,  seated 
as  shown  in  the  cut  (Fig.  16),  holds  a  strong 
(IC  i>.)  convex  lens  about  10  cm.  from  the 
eye  under  examination,  and  between  it  and 
his  own,  when  a  clear  real  image  of  part  of 


•7 

the  funiliis,  inirrtrd  and  magnified  about  four 
diameters,  appears  in  the  red  light  of  the 
pupil. 

In  the  diriTt  mrilntd  d'ig.  17)  (J„.  observing 
eye  must  be  placed  as  close  !o  the  ol)served 
as  the  inlervenlion  of  Ihe  mirror  will  allow, 
when  a  rirliiiil  image  of  a  still  smaller  part  of 


Fit?-  IJ 
Ix>ring  Ophtlialmoscope 

the  fundus  is  seen,  hut  erect  and  magnified 
about  fourteen  diameters. 

Direct  ophlhalmnscopy.  or  Ihe  examinatiim 
by  the  upright  or  erect  inuige,  is  illustrated 
by  means  of  Fig.  17.  A  side  lamp  (L)  is 
used,  the  rays  from  which  are  focu.se<l  by  the 
perforated  mirror  of  the  ophthalmascoix-  (OO) 
and  thrown  into  the  observed  eye  through  the 
dilated  pupil  (P).  The  rays  of  this  |)eneil 
now  cross  about  X  and  impinge  on  the  retina 
and  choroid  nt  (M)  and  cover  the  ocular  back- 
ground from  B  to  B.  Thence  a  sufficient 
number  of  efferent  rays  are  reflected  and  re- 
fracted back  through  the  ocular  media  of 
both  the  observing  and  observed  eyes  to  tlie 
percipient  elements  of  the  former,  at  L. 

Another  illustration  (Fig.  16)  shows  indirect 
ophthalmoscojry,  or,  as  it  is  sometimes  called, 
the  examination  by  the  inverted  image.  A 
divergent    light    pencil    proceeds    from    the 


n    : 


.-.■„  -t  - 


v^"-:-: 


m 


mrf 


«8 


THF   Fl'N'nrs  (Kn.I  Of   BIRDS 


'H),  Hlinin 
Iff     u..    Ii 
the  ciTitri'  II 


■■liowiriK  lln- 


FiK.  irt 

Irjiliriil  (>(ihtlmlm(Mcj>py 
•■.iir«.  „f  th,.  li^,lil  my,  fr,„n  llir  l,„np,  I,.  |„ 


""•   rrlina  at   Zv.   („  U-  fi„„l|v   „.H.h  t  .1   .       I  '  V""'"  '"""'  '"•""''  ''>   ""■ 

-f  tl...  mirr..r,  (X).  '  '  '"  "'"  ''>'■  "'  "»"  "'-•"-^  »'   !•"•  "l"'..i"B  in 


lump.  L.  i„  the  ..plithdlnidsroiH-  mirror  ()0 
which  f.K-iises  tl.f  rays  .,1  '■  Tlu-s.-  Mil.-' 
M-qm-ntly  .liv.TK.-nt  rays  an-  lu.  aia.l.-  paral- 
l<'l  l.y  tlif  convex  I,.,,., an.lar.'  lliusl.rouKlit  ton 
f<HU.s  on  tl..-  n.lina-<.l,oroid  l,y  the  .liontrir 
"pparatus  o,  the  ohserve.l  eye.  Then.e  the 
rellecled  an<l  en.erKenf  rays  follow  the  smie 
path  aii.l  ,„„H.  to  a  f.Kus,  ..i  X.  in  the  .-ve  of 
the  examiner  who  will  si-e  an  inverted  aerial 
iniage  of  the  observed  fundus. 

The  ,./,r/nV  .■>,■//. ilhn,nnoliny  ophlhnlmn- 
■vropr  .hirers  fron,  the  types  just  pieture.l  in 
that  If  earri.'s  its  own  lit;ht  s.Miree  —  a  l,at- 


t<Ty  in  th.-  han.ll.-.  It  is  ,H.,,,liarly  mlapl.-,! 
lo  the  .•xannnation  of  th.-  .-v.-s  ..f  animals 
'.ther  than  Man.  One  is  enal.L.I  ihrou«h 
this  improv.-ment  not  only  f.  .lisp.nse  with 
the  eumhers.mie  si.h-  liKhl  l>ul  to  mak.-  satis- 
fa.tory  examinati..ns  of  th.-  fun.lus  ...uli  in 
"Illy  partially  darkenetl  surn.un.linKs  seri- 
ous e..nsiderations  in  .loin^  fi.-ld  work  with 
^M  s|H-ei<-s.  A  picture  of  th.-  jat.-st  ni.uh-l 
of  the  self-lumin.)us  oplilhalnios.„t«.  is  shown 
in   Kif?.  i\. 

The  fact  that  a  consid.-rahle  jx.rti.)!!  .,f  th.- 
light    tlir.)wn    into    th<-    int.-rior   of    the   ,-ve 


Dirett  Ophthalmoscopy 
Diagram  showing  the  course  of  the  liirht  rav,  fmm  »k     i 
.hence  they  a.e  refle,.ted  directly  upon  the  oW  v  uTet  n     TL'i^  '"th'^  "'""'•  ™' 
reflected  through  ,he  opening  in  ,he  mirror,  OO.  J^^Z^^,  J^^ 


the 


Wi^^m-^Sl-^MM 


felf" 


OPHTHALMOSCOPY  OF  THE   VERTEBRATE  EYE 


Fig.  18 
Relativp  Position  of  Observer  and  Oliwrv.-.!  in  Direct  Ophthalmo«x)py 


Fig.  10 
Relative  Positions  of  Examiner  and  Examined  in  Indirect  Ophthalmoscopy 


m\ 


ii'i 


m 


THE   Kl  NDUS  OrULI  OF  BIRDS 


IhroiiKh  the-  pupil  in  rf(l.<  l,-,l  liy  fhc  Mrilr- 
liirr.  ..f  (I,,.  l.mkKn.iilt.l  int..  l|,i.  ,.,<•  „f  Jhr 
..l«,.rx,r  ,n  iIh-  primipl,.  of  Ihr  (>phlhalin.«- 
<<>|M'.  M,,ri-,.v<r.  Ihix  r<-(l,T»i(.n.  or  ratJu-r 
rtfra.iiuri,  nf  i|h-  iiiriHcnt  ruy*.  tii.Hlitii'il  \,y 


Mortim  (>pli(halniiiHc<i|M' 

the  .Jmrarter  of  IIr-  nu-dii.  throiiRh  wliid, 
they  pnss  furnish  tlu-  wonderfully  vjiric.l  „n.l 
••(.lore.!  pictures  ohscrved  in  the  .Kuliir  l,i„k- 
KroiuKl.,  of  all  the  verlehrntes. 

This  brief  account  of  the  ophthalnMiscojH. 
and  Its  method  of  employment  is  oir.red  for 
file  benefit  of  those  who  have  not   use<|   the 
instrument,   hut   no  do.scrif)li(m   of  ophthal- 
moscopy will  much  aid  the  zcH)loKist  in  ac- 
•luiring  a  practical  knowledge  of  its  applica- 
tKin   in   the  actual  examination   of  animals' 
eyes  even  in  the  favorable  surrounding  of  the 
darkened    laboratory.     Only    a    number    of 
months  spent  in  the  exploration  of  the  eyes 
of  such  domestic  animals  -  including  Man  - 
as  are  most  readily  aewssible  and  easily  ob- 
served, followed  by  ophthalmoscopv  of  wild 
species  obtained  in  field  work,  will 'make  an 
exjM-rt  of  the  stu.l.'nt.     While  the  writer  will 


not  nuy  thnt  «  prootical  knowledge  of  throph- 
thHlmoscofK"  in  f»»fntial  to  the  training  of  thr 
Mienliti.ioologi«t  yet  it  ii  an  instrument  that 
fiirnishr*  prrei«.  and  valuable  information 
which  the  naturnlixl  cannot  afford  to  ignon-. 

A.    The  Fiindut  (hiiU  or  background  oj  the 
Inhrnal  Eyr  in  Man. 

On  account  of  the  extensive  literature  on 
this  subj.K-1  and  lHtau«-  the  human  fundus, 
normal  and  abnormal,  hait  Ut-n  .arefully  and 
thoroughly  explored  by  many  ..bservers  for 
over  half  a  «entury  no  study  of  comparative 
ophthalmology   in  complete   without   at    least 
a  short  account  of  the  ophthalmoscopic  fin.l- 
iiiffs  in  Man.     In  the  writer's  K,wy,-l„,»;lla  „f 
OlMmlmiihg;/,    \„\.    Nil,    r>.    .Ml. 5    ,7    .i,,,., 
M«H.re.i    Hall   gives   a   good    account    of   the 
fH'BUtifully  col(,red  ophthalnios<opi<.  picture 
one  seen  in   the  <l,.plhs  of  the   human   eve. 
The  part-s  of  chief  interest  in  th<-  human  fun- 
dus are  the  optic  disc,  the  bhwKl-ves.seN,  the 
macula  liitca,  and  the  choroid,  and  they  fur- 
nish a  .satisfactorj-  comparative  study  intro- 
diictory  to  n  consideration  of  avian  fundi. 


KliTtrir  SolMumini.iis  Optithalmoscope  (de  Zeng). 

The  optic  disc  is  situated  about  a  mm.  to 
the  nasal  .side  of  the  posterior  pole  of  the  eye, 
and  is  the  point  of  entry  of  the  optic  nerve 
into  the  retina.  It  measures  from  1.4  to  1.7 
mm.  in  diameter  and  is  generally  circular  or 
ellipsoidal   in    shape.     Near   its   centre   is   a 


^i^- 
^^i- 


,'  -v. 


^ji,'^^}fs^:M 


^k>%\  I  ■■■'  .■2»:i  f  ^.  «?^!\'-  -•?  '•a'»5v:ja«i»  w^tsmx: 


OPHTHALMOSCOPY  OF  THK   VERTEBRATK   KYK 


SI 


iloprt'Miiun,  th(>  phykiologir  <>xcutiiliuii,  whiili 
marks  lh«'  divornpncv  cif  iiprvi--iil>re«.  Tin- 
fxcavatinn  i»  funncl-xImiM'H,  tl'  Imw  Im'jiik 
Hiili-rior.  A  trncr  of  Ihf  liyiiioid  arli-ry  of 
fctn]  lift-  is  tN-t'asiunally  Mfii  Uerr  a.i  u  thrfiiil 
iif  i-onrHftivi-  tisDUc  running  frnni  tlii>  papilln 
into  I  hi-  vilr«'ou«.  SiirrouiuliiiK  flu-  luipilla 
itrt-  two  riM)(^:    iin  iniirr,  iIik'  Io  i-xpoiiiri'  <>f 


(ilimt, iliM-  to  thi^  fnct  that  i  .<■  nmlulUry  cover- 
iiift  of  t  lie  uxiit-oylinili'rt  t>\  i  .1 1  in  I  he  fitire-lnyer 
of  the  retina.  In  tmh  11  iiixe  the  fumluit  showi 
a  pHti'li  of  a  lirilliunt  white  color  extemlinK  nut 
from  the  ili.ie.  (ienerully  the  white  area  in  in 
rontart  with  the  i|i<i<-.  It  rarely  oocurt  that 
the  opn<|U)-  fil)ri'!«  are  fotinti  at  a  K^'nt  di'ttance 
from   the  nerve-heail  or  that  they  iK-rupy  a 


Kg.  « 

Diagram  Showing  the  Relations  of  the  Parts  in  the  Human  Fundus  Oruli.     a,  sclera;   b,  choroid; 
'.  macular  region;   i,  optic  disc;   3,  superior  nasal  artery:   4,  inferior  nasal  artery;   5,  inferior 
temporal  artery;  6,  superior  temporal  artery;   T,  temporal  side;   N,  nasal  side. 


e,  retina; 


the  sclera,  is  whiti.sh,  and  is  culled  llie  scleral 
ring;  and  an  outer  one,  due  to  the  showing  of 
choroidal  pigment,  is  named  the  choroidal 
ring.  At  the  bottom  of  the  excavation  a 
few  dark  spots  arc  seen,  from  the  gray  stij)- 
pling  of  the  lamina  crihrosa.  In  color  the 
papilla  is  grayish-pink  or  reddi.sh,  and  stands 
out  in  marked  contrast  to  the  reddish-yellow 
of  the  remaining  parts  of  the  fundus.  The 
color  of  the  papilla  varies  with  the  age  and 
complexion  of  the  individual,  the  color  of  the 
surrounding  parts  of  the  fundus,  and  with 
the  illumination  used.  A  common  anomaly 
is  the  presence  or  persistence  of  opaque  nerve- 


large  area  of  the  fundus.  The  physiologic  cup 
or  depression  may  occupy  a  large  part  of  the 
nerve-head,  but  never  extends  to  the  scleral 
ring.  Under  normal  conditions  inany  varia- 
tions are  seen  in  the  size  and  depth  of  the  cup 
and  in  the  arrangement  of  the  lilood-vcssels. 

The  blood-re.i.iels  are  the  central  artiry  and 
vein  of  the  retina.  They  run  in  the  nerve- 
fibre  layer  of  the  retina,  and  often  present 
variations  of  distributic  »  The  middle  of 
the  fovea  centralis  has  n    '  •'■  'od-vessels. 

While  it  is  often  staled  that  the  retinal 
vessels  can  be  seen  on  ophthalmoscopic  ex- 
amination, as  a  fact  it  is  the  column  of  blood 


■■r^^''n;?lr'^'')t?  «*f  *f  ,«'i?-'V="«::':C '^''--  'i^-% 'r^-yn  K'.-^  ■ 


.mr 


Si 


and  not  the  ve.scl-wall.  which  i.s  visible.     In 
the  larger  retinal  vessels  the  l.l..od-eolu.nn  in 
he  arteries  is  hriditer  than  (hat  in  the  veins 
In  the  snu,ll,-r  l.-.,„.hes  this  .lifFerenee  is  less 
■narked.      The  l,ri«l,|,r  e.,l„r  ,.f  the  arteries 
js  due  to  the  presence  of  a  central  streak  of 
I'Kht.  which  IS  less  marked  in  the  veins.     The 
cause   of   this    liKl.t-streak    is    not    .Icfinitelv 
known.     The   retinal    artery,    under   normal 
oond.tions,  rarely  p,>lsat..s.  I,„t  venous  pulsa- 
tion occurs  spontaneously  in  from  00  to  75 
per   cent  of  normal  eyes. 

Besides      the      l.Io^d-ve.ssels      enumerated 
•iDove    It  IS  necessary  to  mention  the  cilio- 
retuHd  ,-es.seh.     The    ■   are  comnionlv   small 
solitary   ves.sels   which   arise  from   the  circle 
o    Haller.  and  emerge  .*  the  Icmporal  l.order 
of  the  disc.     Such  a  vessel  may  come  from  the 
central  vessel  in  the  substa,K.e  of  the  nerve 
and  may  be  of  larger  size.     (Jenerallv  it  sup- 
plies blood  to  a  .small  area  between  U,e  disc 
«nd  /nacula.     Cilio-retinal  vessels  are  present 
in  from  10  to  KJpor  cent  of  normal  eyes 

The  mncuL  lutea  ("yellow  spot  "  of  Soer  ■- 
■".•nuK)  ,s  situated  about  .'!  mm.  to  the  outer 
side  of  the  optic-nerve  head,  and  sliKhtlv  be- 
low  the   horizontal   meridian.     It    is   a  "spot 
'la.ker    than    the    surrounding    retina    an.l 
apparently  devoid  of  blood-vessels.     It  is  the 
area   of  greatest    visual   acuity.     The  centre 
of  the  macula  presents  the  foveal  reflex,  while 
he    periphery    shows    a    whitish,    glistening 
HR,  or  halo,  known  .-.s  the  macular  reflev 
U.frerenees  m  the  appearance  of  the  macula 
.n   iiH  ivduals  are  doubtless  due  to  several 
(mostly  domestic;  eaus,-s:  to  the  .lilfercnce  in 
methods  of  examination;  to  ditrerenees  in  the 
age,  complexion,  race,  and  refraction,  as  well 
as  to  variations  in  the  distribution  of  pigment. 
There  are  several  forms  of  (ophthalmoscop- 
cally  vi.s.bhv  macular  rings.    Lindsay  Jc hnson 
states  that    the   most    common    is  a  bright 
sen,  ,ll,.,ting  reflex  resembling  shot-silk,  verv 
■narked  in  dark  eyes,  scarcely  visible  in  fair 
oiies,  an.l  best  .seen  with  feeble  illumination. 
1  his  ring  ,s  supposed   to   be  due  purflv  to 
reflection    from   Muller's    fibres,   where  ihev 
expand  into  the  internal  limiting  membrane, 
and  partly  to  the  fibrous  sheaths  of  the  vessels 
which  lift  up  the  retina  over-lving  them 


THE  FUXDrs  OCULI  OF  BIRDS 


Tlie/o,ra/  reflex  is  found  in  the  centre  of  tlie 
macula  as  a  verv  small  ring,  or  as  a  circular  or 
hor.sesh.K'-sha,H-o  spot  of  light,  or  as  a  "comet- 
lare.  It  ,s  due  to  reflection  of  the  edge  of 
the  fovea. 

The  ehornid.     While  each  ocular  tunic  con- 
ributes  something  to  the  highly  colored  oph- 
thalmos,.opic  picture,  the  chief  part  must   be 
en'dited  to  t  he  choroid.     Light  reflecte.l  from 
he    m.rror    „f    the    ophthalmosco,K.    pas.ses 
hnuigh   the   transparent   part  of  the  retina 
to    the    pigment    epithelium,    and    is    partly 
absorbed,   partly     reflecte.l.      Although     the 
piKuient  layer  belongs  embryologi<.allv  to  the 
retina,    it    generally   adheres    to    the"  retinal 
sur  ace  of  the  choroid,  and  is  accredited  oph- 
thalmoscoj.ically    to    the    latter    tunic      Tho 
.right ness  of  the  fundus  picture  depends  on 
the    amount    of   pigment.     The   greater   the 
I>iK|nent,  the  greater  the  absorption  of  light 
and  the  darker  the  fun.lus  picture.     In  the 
..egro  and  the  native  of  India  the  fundus  is 
of  a  brownish,  brown-red,  or  slate  color,  while 
'■«    the    .Vnglo-Saxon,    and    particularlv    in 
l>lon.les.  It  is  of  a  bright-red  color.     If  the 
pigment  layer  is  very  thin,  the  choroidal  ves- 
M-ls  are  correspondingly  expose.l  an.l  arc  seen 
a.s  a  network  of  large,  flat  ves.sels,  without  a 
l:Kht-streak,  between  which  are  spaces  of  light 
or  <lark  color.     They  are  .seen  best  in  albinos. 
It    IS    generally    impossible    to    diflFerentiate 
l.e  ween    the    choroidal    arteries    and    veins, 
although  at   the  equatorial  region  the  latt.T 
converge   to  form   the   venffi  vorticosie.     In 
l-runettes  the  vessels  appear  as  '-light  streams 
separatcl  by  ,|ark  i.slands,"  because  the  spaces 
are  more  deeply  colored  than  the  ves.sels 

The  srh-ra,  which  may  be  sjiokt-n  of  as  tlie 
panel  on  which  the  fun.lus  picture  is  painted 
■s  c..mn,only  invisible,  being  coverci  by  th,' 
"early  .,pa,,ue  choroid.     Vet   it   is  probabi,. 
t  .at  in  all  ,.yes  some  light  passes  through  the 
ehor.,.d,   an,|    thus   the  .scl.ra   has   some   in- 
|h""nce  on  the  ophthalmos.-opic  picture,  serv- 
■■ig  to  make  it  lighter.     In  albinos  the  scleri 
appears  as  a  white  surface  between  the  cho- 
roidal   vTssels.     It    is    best    .seen    where    the 
choroi.l  Ks  ab.sent,  as  in  coloboma,  or  patho- 
logically  as   a   result   of   destruction   of   the 
retina  and  choroid. 


■r::r>.-^-^' 


■^: 


ClIAITEK  VI 

OPHTHA  -M.  )SCOrY  OF  THE  Fl'NDl'S  IX  LIVINX;  BIRDS 


Tin-;  nit'lliod  employed  liy  the  writer  in  ex- 
iiniiiiiiif;  tlie  l)a<kj,'rournl  of  tlie  eye  in  living 
Hirds  does  not  niiich  differ  from  tli;it  of  the 
physician  in  liis  examination  of  human  eyes 
as  described  in  the  previous  cliapter. 

For  a  proiMT  exploration  of  the  vertehrate 
fundus  it  is,  as  previousl.\;  stated,  hi^lily  de- 
siral)le  tiiat  tlie  pupil  Ic-  widely  dilated. 
This  is  accomplished  in  M.m  and  other  Mam- 
mals hy  such  mydriatics  as  alroi)in,  hom- 
atropin,  euphthalniin,  etc.,  which  hriiif;  about 
an  enlarged  pui)il  inaiidy  by  inhibiting  the 
action  of  the  non-striated  sphincter  muscle 
fibres  of  the  iris.  In  Birds,  however,  these 
a,i;<'nls  have  little  dinrt  elfect  on  the  striated, 
voluntary,  sphincter  musculature  of  the  iris; 
hence  they  are  of  little  value  in  an  ophthal- 
moscopic examination  of  most  Birds.  One  is 
oblified,  therefore,  to  resort  to  such  agents  as 
galvanism,  nicotine,  strophanthin,  curare, 
sliptiein,  etc.,  and  to  such  drugs  (eserin. 
alropia)  as  render  the  bird  unconscious  with- 
out actually  killing  it. 

In  collecting  the  heads  of  birds  for  niacro- 
seopical  and  histological  studies  the  writer 
found  tliat  satisfactor.v  ophthahiioscopic 
views  of  the  fundi  can  be  had  a  few  minutes 
before  and  after  the  death  of  the  specimen, 
during  whidi  period  the  pupil  not  only  dilates 
(/(/  miij-imiiiii  but  the  bird  does  not  use  his 
third  eyelid.  Many  of  the  api)ended  rcj)orts 
were  gathered  in  this  way. 

Owing  to  the  peculiar  arrangement  of  their 
lacrimal  apparatus  (.s<h!  the  writer's  work  on 
this  subjeei)  iiuids  instilled  into  the  eye  (con- 
junctival sae)  of  Birds  run  immediately  into 
the  throat  and  gullet,  there  to  be  absorbed 
and  to  produce  precisely  the  same  systemic 
elfeets  as  if  they  were  poured  directly  down 


the  throat  of  the  animal.  (Ireat  care  should 
be  used,  therefore,  in  using  eye  drops  for  their 
expected  effect  upon  the  visual  apparatus: 
if  poisonous  for  the  bird  they  may  cause  his 
death  in  short  order,  and  rare  and  valuable 
specimens  may  be  sacrificed  to  the  ignorance 
of  the  observer.  The  writer  has  not  the  least 
doubt  but  that  some  of  the  so-called  mydri- 
atics or  pupil-dilating  drugs  recomniende<l  for 
an  exann'nation  of  the  ocular  interior  of  the 
Bird  act  as  .systemic  intoxicants  and  not 
specifically  upon  the  iris  muscles,  as  is  the 
case  with  the  manmialian  eye. 

As  :in  example  of  this  action  of  the  so- 
calli'd  mydriatics  on  the  eyes  of  birds  the 
writer  once  fell  into  the  same  error  as  other 
still  earlier  observers  in  attempting  to  dilate 
by  atropia  the  i)upils  of  a  Yellow  Parakeet 
{Mrlopttitlnriis  iindulatiis).  This  bird  w-as  an 
adult  individual,  .sex  unknown,  in  captivity 
for  six  months.  In  dull  light  the  pupils 
were  -2. .5  mm.  wide,  contracting  irregularly 
to  1.,)  mm.  A  single  drop  of  a  1%  .solution 
of  atropia  sulphate  put  into  the  eyes  appar- 
ently dilated  the  pupils  ad  max  (3  mm.)  in 
H  hours,  but  as  the  bird  was  taken  ill  a  few- 
hours  following  the  instillation  (stupor,  ver- 
tigo, quick,  weak  heart  and  final  unconscious- 
ness) and  died  30  hours  after  the  use  of  the 
<lrops,  it  is  quite  likely  that  its  death  was  due 
to  the  poi.son  that  ran  into  its  throat  from  the 
conjunctival  sac.  The  writer  had  a  similar 
experience  with  a  number  of  other  birds. 

The  following  notes  were  made  of  experi- 
mentation intended  to  determine  the  best 
mydriatic  for  the  Bird's  eye,  especially  for 
field  work. 

Laboratory  Xote.i  of  Experiments  on  the 
Pupils  of  Passer  domesticus.     One    drop    of 


[38] 


S4 


•»  to  ,Hi,„i„„  „  „.,,„  ,„  I  'J,*: "-. "°  '*" 

•lisWv  "Bro™-"  ,„1  '  •  ""^  '•""""■ 

1  .      »'"«8J     in  4  niiniitos.     l(i-9n  .  .. 

very  shght,  if  any  difference  in  pu^s     Vl"' 

recovered  in  fi  -^^     '"  ""'^'  """"'e  but 

recovered  in  five  nnnutes  so  as  to  sit  un  in,! 

Hv*.„....ner,p„;nrit';r 

lay  on  its  hJi-        J^  .^oSBi'"  w  i  min.; 

diffieuhv  de    ,t  Tn      """■    i'-"*'''"^'   with 

left;   sen;iSt;d^S:"'''"'^''^''"*^^ ''"''•' 
March  30,  191  ^  "l  -qn  n  ,.      t. 

1%  n,.o/,-„  nVo  Ihe  leVev.    M.'  ""'  "^^"P  °' 
All   I  '^''^  eye  of  three  adult    o 

All  became  more  or  Jess  "wobbV'  in  L 
nnnutes,    recovering   almost   entirely  ?„  T," 
minutes.    At  4  p  M  t\,^         -,     ,  .  v    in    15 


THE  FUNDUS  OCULI  OF  BIRDS 


iJight  |)iij„|  unaffected  at  4  p  m  •  i      i  .. 

normal  at  4  ...  „  ""^  *  ' '  *'• ''"'h  Pupils 

Jfarch  20,  m}.  Examined  pupils  in  one 
o-  and  two  9  1 1 ,;  ♦„  9\  '  „  pu|'"s  m  one 
TV.  -  *   2  nim.   in   dianie»»r 

They  contract  pron.ptiv  in  light  to  .  T 
Nicotin,  both  K-  and  ^r-         *"   '   '^   ^    """■ 
the  birds      On     A         \ "  "*"""*  *"  "''■■""'" 


1010      V       /•  -^^  -^^  **••  -^lareh  •iH 

1912.     Negative  results  at  12:00 

purpose         ^  "^""'   °°^  -"   "-   for   the 
Experience  has  proved  thnt  tKo     in 

'ens  (to  make  sure  that  there  is  in  tin     u 
in  «  dark  roon,      Tl,       ,    T"  °"  "  '*"'' 

assistant  seated  opposit^         ^  ''^  "" 

In  /fW  «.or*  both  the  observer  and   I.; 
assistant  may  Wl  on  the  earth  under  ^ 


OPIITIULMOSCOPY  OF  THE   FUNDUS  IN  LIVING   BIRDS 


large,  bl.  k  uiul>rclla,  or  make  tiic  examina- 
tion in  u  darkened  tent;  in  public  or  private 
aviaries  the  examination  can  often  be  made 
after   sunciown. 

A  four  dioptre  convex  lens  must  be  placed 
in  front  of  the  eyehole  of  the  mirror.     This 


as 

species  that  present  invariable  ophthalmo- 
scopic pictures.  It  will  be  found  that  after 
two  or  three  generations  of  inbreeding,  con- 
finement and  domestication,  changes  occur 
in  the  ocular  apparatus  coincident  with  varia- 
tions in  other  parts  of  the  organism. 


Fig.  43 

Method  of  Examining  the  Bird's  Eye  with  the  SelMumiuoiu 
Elet'tric  Ophthalmoscope. 


"indirect"  method  (see,  also,  page  29)  gives  a 
comparatively  small,  inverted  image  of  the 
ocular  fundus.  It  corresponds  to  the  low 
power  lens  which  one  uses  in  the  preliminary 
examination  of  a  microscopical  .section. 

The  examination  by  the  erect  image  will,  on 
the  whole,  be  found  the  most  satisfactory 
method,  although,  as  in  viewing  the  human 
fundus,  it  is  advisable  to  use  the  indirect  plan 
at  the  outset.  The  self-luminous  ophthal- 
moscope is  quite  satisfactory  for  both  these 
purposes. 

In  making  an  examination  of  the  avian 
fundus  it  must  be  remembered  that  it  is  wild 


The  facility  (or  otherwise)  with  which  the 
ophthalmoscope  can  be  used  depends,  in  a 
large  measure,  upon  the  conduct  of  the  bird 
under  examination.  For  instance,  it  is  im- 
portant that  the  macular  region  be  carefully 
explored  and  it  can  generally  be  seen,  but 
throwing  the  light  on  this  very  sensitive  area 
often  makes  the  animal  restless  and  the 
greatest  gentleness  should  be  observed  to 
keep  it  quiet  if  a  complete  examination  is  to 
be  made.  Most  specimens,  not  excepting 
the  Eagles,  Hawks,  Vultures  and  other  large 
birds  can  be  hypnotized  and  so  quieted  for  the 
period  of  an  ophthalmoscopic  examination. 


Zi.  L»^\^M^'a!Xgrm!SES\U.'I^-.frt^-f'f'''lWf--m~  y-Mu*t  '"iT.^J»rf'^4«..l 


f'S'^^!? 


^'vjitmsja 


■Mi 


Wr.l  relaxes  i      ,1  "  ■"*'?^'-^-  '••■'•^«"'-  ""• 

"^'■"lly   l.e  turned  i„  1.     1    ",'';""'   '."" 
t.^-iUi.M.bserver/s:eVi'T     '''■"•''"' 

of  occasional  mntr    ♦     "",'""'  •'"«!  ''('cause 

.L.- .;;.;.;;';;,;;:;:'•'■'■'' ^  "■"-'■■» i 

As  an  extended  study  of  the  eve    ,  f  i-   ■ 
•^"•ds  is   not   without   ;i-     /      ^-^f^of  livniK 

buf'irCr'i.ii.jrvr"'^-^"'^'^-'-"™- 

'^         ""   °^  Bentley's   California 


THK  FUNDUS  OCULI  OF  BIRDS 


^l^iascope  had  i,l-,v.  I  .        r''f-'"'>""<'U.s 

''^■-•'■''-^inuMvereinlpr.!.        '''''•''*■' 

-""".;ronepos„ion«,;,rji ;;:;;;";:; 

"iradion,  Hindus  apnearanc.s  «(,. 
n.a.le  without  .liffieullv      Fin  !        i ""' 

^<' '"inutes  or  half  an    our' whJ.',;^'"  "'"•'* 
"/'-■.^"Pleted.  the  bird  refund  to  ;''''*■'" 

--and  had  to  he  pushed  ;:rt£,^";,::; 

"'-nu.|.eean,e  his  lively  .elf  asa  "" 

"•"1  tax  the  p<Ts,neran,.e  of  fh       .  '"■'' 

the  utmost       Jt   ,-.    ,  "f  »he  observer  to 

'"W.    also     -.r..    )i       e     ■  .^*''^™"<(-     Annov- 

-siot     IL-       ,  *''^^"g'"^•^•    reflections    an.l 

snoi-silK     colors  that  nl'iv  n,-,...  .i 
areas  in  some  b,r,l      .    .    '  '^  ""^  '■'''"">1 

-rnersant    w^).  "';'•''  ""'  ^  ^^ftVientiv 

'■"''■'-;i:;tr:ti;u'dr''"'"^^'''''- 
:f ;;  e;i.:^b;;;^ 

--o.eSt-2-----^ 


5iilfc«Ii^in«Slj^ff;>^^ 


m 


OPHTHALMOSCOPY  OF  THE  FUNDUS  IN  LIVING   BIRDS 


37 


FiR.  H. 
Nubian  Ostrich  {.:itruthio  camelua). 


Pig.  25. 
American  Ostrich  {Rhea  americana) 


Kig.  il. 
Kini  or   Apteryx  (Apteryz  mantetli). 


Fig.  28. 
Martiiicta  Tinamou  (Calndromas  elegam). 


*"'8««-  Fig.  29. 

Westerma..-,  Ca^owarj-  {Casuariu,  occipitalU).  BraziUan  Scriema  {Cariama  crutata). 

Diagrams  of  the  Pecten  as  seen  by  the  Ophthalmoscope  in  Various  Species  of  Birds. 


iii 


38 


r,i.r.k-ns  „f  till-  London  Zoological  society  the 
opiilliMlnioscopic  apiK-arances  of  soverafhun- 
drcl  avian  and  other  eyes.     The  .letaiU  of 
these  fundus  views,  as  revealed  l>v  the  oph- 
thalmoscope in  many  species,  are  described 
and  dt7)icteu  in  Chapter  X  an.l  elsewhere. 
A.    The  Avian  Eyegrnund  in  General. 
The  average  eyeground  or  fundus  oculi  of 
"H.st  Day  Birds  resend.les.  as  much  as  anv- 
thing.   the   texture  „f  the  so-called   "scotch 
•nixlurcs"  in  .smooth  finished  cloth-     usuallv 
light  l.rown,  gray,  gray-blue,  blue  mi.xe.l  with 
striate  rays,   or  fine   concentric   marking  of 
ighter  gray  or  white.     Scattered  over  this 
background  are  numerous  yellowish,  yellow- 
white,    brown    or   gray    points   of   pigment. 
Although  this  matter  has  not  yet  been  satis- 
factorily determined  yet  these  punctate  de- 
posits are,  in  part   at   least,   the  colore.)  oil 
droplets  described  in  Chapter  IV. 

Nocturnal  Birds  have,  almost' in  variably 
yellow-red.  orange,  orange-red  or  reddis'h 
brown  fundi,  with  the  choroidal  vessels  plainly 
visil)le  through  tlu.  .semitransparent  retina 
>omc  of  the  (Jwls  j,resent  almost  a  scarlet 
vermilion  eyeground,  and  this  intensity  of 
colors  appears  to  be  peculiar  to  Strigiformes. 
tor  this  reason  alone  might  say  with  confi- 
dence that  the  New  Zealand  Owl  Parrot 
{Struigop,  habroptilus)  belongs  to  this  order 
and  not  to  Psittacif— »s  or  to  Cuculiformes 
in  one  of  which  he  is  commonly  placed 

Ophthalmoscopy  of  the  areas  A  distinct 
vision  in  Uirds  supplements  the  macroscopic 
and  microscopic  examination.    In  many  in- 
stances It  affords  a  better  idea  of  the  relations 
of  these  area;  than  does  any  other  means  of 
observation;  at  least  this  is  true  of  most  avian 
fundi  explored  by  the  writer.    As  a  rule  the 
deep,  single  fovea  and  its  surrounding  macular 
region  are,  other  conditions  being  favorable 
readily  observed  by  means  of  the  mirror,  and' 
their  locality,  comparative  size,  component 
parts,  coloration,  etc.,  easily  depicted.    Con- 
trariwise, a  shallow  or  organically  ill-defined 
yellow  spot"  is  not  so  readily  made  out. 
Hand-like  areas  are  also  better  defined  by  the 
aid  of  a  magnifying  glass  and  in  prepared 
half-eyes,    although    in    the   fundus    of   the 
Secretary  Bird  (Plate  XXXI).  of  the  VVhite- 


THE  FUNDUS  OCULI  OF  BIRDS 


bellied  Sea  Eagle  (Plate  XXXIV)  and  of  a 
numl>er  of  other  bimacular  species  the  ribbon 
of  tissue  IS  well  shown  by  the  mirror. 

With,  ijcrhaps.  this  exception  the  macro- 
scopic description  of  the  area  centrales  given 
not  only  in  the  Usts  of  Chievita  and  Slon.ikcr 
but  m  Chapter  VII  corresponds  in  a  remark- 
able fashion  with  the  ophthalmoscopic  fin.l- 
ing.s  described  and  depicted  in  this  work. 
.Nothing  has  been  discovered  in  this  study  of 
the  avian  fundus  by  the  aid  ot  the  mirror  that 
IS  likely  to  add  to  or  subtract  from  the  classi- 
fication of  the  types  of  central  vision  sug- 
gested by  the  writer  in  the  same  Chapter. 

The  Pecten  and  Optic  Disc 

Viewed  ophthalmo.scopically  the  avian  mar- 
supium  or  jH>cten  exliibits  three  fairly  definite 
varieties  which  may  be  classified  as  follows: 
I.    ThoHc    pectens    whose    mass    uniformly 
springs  from  and  equally  coters  the  optic  disc 
^uch  pectinate  bodies  do  not  extend  into  the 
vitreous  cavity  farther  than  the  length  (often 
less)  of  their  widest  segment,  and  th.y  are 
sessile  on  t  he  face  of  the  papilla.    Examples  of 
till ,  form  of  pecten  are  seen  in  Nyeticorax 
nyeUcorax  (Pig.  45).  Halimua   Uucoccphalus 
(I'lg.  ..()),     Caprimulgus    europeus    (Fig.  Co) 
Strixflammea  (Fig.  59),  Serpentarius  (Fig  52)' 
Struthio  camclus  (Fig.  24),  Canctoma  cochle- 
ana  (Fig.  46).  Casuarius  occipitalis  (Fig  26) 
Spheniscus  demersu»  (Fig.  37).  Tinnunculu's 
alaudanus  (fig.  55).  Calodrmnas  eUgans  (Fig 
28)  and  Symium  aluco  (Fig.  58).    This  method 
of  arranging  the  pectinate  tissues  makes  pro- 
vision for  a  blood  reservoir  large  enough  to 
supply  nutritional  needs  but  so  placed  that  it 
docs  not  materially  obstruct  visual  or  light 
rays.    Such  a  disposition  and  configuration 
"f  the  fundal  organs  meet  the  needs  of  many 
species,  among  them  Eagles  and  Owls,  wh-. 
re(|uire  (and  have)  very  acute  vision. 

II.  Some  pectens,  while  they  originate  from 
the  whole  surface  of  the  optic  disc,  immediately 
slope  away  from  the  visual  axis,  approach  the 
bulbar  wall  and  terminate  without  projecting 
far  into  the  vitreous.  In  this  type  there  is 
generally  a  disc-length  or  more  between  the 
free  terminal  of  the  pecten  and  the  posterior 
surface  of  the  crystalline  lens. 


OPHTHALMOSCOPY  OF  THE  FUNDUS  IX  LIVING   BIRDS 


3» 


FiK.  30. 
Ilarlecjuin  Quail  {Coliirnix  hutrionica) . 


Fig.  S8. 
Common  Wood  Pigeon  (Columba  palumbiu). 


Fig.  31. 
Brush  Turkey  {Catheturua  laihami). 


Fig.  34. 
Victoria  Crowned  Pigeon  {Goura  vidoria). 


fig-  3«.  Fig.  35. 

Yarrell's  Curassow  (Crax  globoaa).  Wonga  Wonga  Dove  {iMcotarcia  picata). 

Diagrams  of  the  Pecten  as  seen  by  the  Ophthalmoscope  in  Various  Species  of  Birds. 


it  i| 


■'1  : 


40 


THE   FUNDUS  OCULI  OF  BIHDS 


Fig.  36. 
Ipwahn  Rail  (Aramidet  ipeeaha). 


Fig.  87. 
Black-footed  Penguin  {Sphenucu,  demtrnu). 


Fig.  SO, 
Herring  (Jull  (Lariu  argentaliu). 


Fig.  40. 
Great  Black-backed  Gull  (Lanu  maHnu,). 


Fig.  38. 
Puffin  {Fratercula  arctiea). 

Diagra,ns  of  the  Pecten  as  seen  by  the  Ophthalmo«:ope  in  Various  3pede,  of  Bird,, 


Fig.  41. 
Stone  Plover  (Qedicnemiu  acolopax). 


OPIITFIALMOSCOPY  OF  THE   FUNDUS   J.\  MVIN'(;    HIRDS  41 


Fi«.  *i. 
Little  Bustard  (Telrax  teirax). 


Fig.  48. 
Kagi  i    Rhinochetui  jubalui). 


Fig.  15. 
iNiglit  Hrruii  (S'ycticorax  tiyeticorax). 


Fig.  46. 
Boat-billed  Night-Heron  {Cancroma  cochltaria). 


Fig.  44.  Fig.  47. 

European  Bittern  (Boiaum  tUllarit).  American  Jabiru  {Mycteria  americana). 

Diagrams  of  the  Pecten  as  seen  by  the  Ophthalmoscope  in  Various  Species  of  Birds. 


■tri 


n.3*.-"w."w-7;y 


'Ldia:.x^Hiu«:!i'i3»<«i;i;:iaBKrtGSb:.j2:wiBcr^u.<j>i; 


^!xsiSi.;r^'Mi7^ji^'^,i-^'ix;: 


4« 


THK   FUNDUS  OCVLl  OF  BIRDS 


Fig.  48. 
Blue  Snow  Goose  ^C'lun  caruluetm). 


Kig.  49. 

Red-bUled  Tree  Duck  (Dendroeygna  autumnalu 
ducolor). 


Pig.  il. 
Cormorant  (Phalaeroeorax  eatho). 


Fig.  M. 
Secretarj-  Bird  {Serpentariut  crUtatui). 


Fig.  50.  ... 

Fig.  53, 
Gannet  (Sula  bai'MM).  .„  .     ,„ 

Lttmmergeier  (GypaHtut  barbatui). 

Diagrams  of  the  Peoten  as  seen  by  the  Ophthalmoscope  in  Various  Species  of  Birds. 


OPHTHALMOSrOPY  OF  TIIK   FirXDrs   I\  MVINT.   BIRDS 


Fi({.  54. 
Whitr-bf llinl  S«'B  Kagle  (Haliattiu  Ifui-ogaMer). 


Fig.  17. 
Rurmwing  Owl  (Speoiyio  eunieularia). 


Fig.  55. 
Common  Kestrel  {Tinnunculut  ulaudariut). 


Pig.  iS. 
Tawny  Owl  (Symium  alueo). 


Fig.  SO.  Fig.  59. 

Americim  Bald  Eagle  {Haliattiu  leucoeephalxu) .  British  Scrcech-Owl  (Strix  flammea). 

Diagrams  of  the  Pecten  as  seen  by  the  Ophthalmoscope  in  Various  Species  of  Birds. 


m 


'SI 


44 


Mm.  fimU  rx«,„,,| f  ,hi,  torn,  in  Cnl^ml.,, 

I»ih,mh,uil-,K.  33).r,„„/„,,,,«„r„.,  ,Fi.,   ,w 
CnthHur,,,  ln,h.mi  ,  F.„.  ;„  ,  ,„ru,  „rgr,„„,u], 
(l-i«.  39).   A.   m„rin>i^   ^V^lt- M)u  KhimHh.i,,., 
Main.    ihiuiSi.    (iouru    r„l.,ri.,    (FiK.'J*) 
<  h,„  crrul.,,;,,.  ,K,„.  4H,.  .»/^,,,„«  a„„.r/,«,»i 
(fix-  »7i.      SiHoljil,,     n,„in,l,iri,i      fFi«57i 
SInngnp,     h„l,rn,,til„,      i  Kjj,,    ,|<,.      r/,„^,„,;; 

«»»/;»«,.  ,ri«.  «(i).  niin,  „„„rw„„.,  ,F,„  i,„ 

•V//..  hn....,,,,,,  (|',„,  .«),.  //„//„,,/„.,  k,r.,y,„l,r 
<H«  -IK.  Trnvi/,,,,  ;/„/,n/«i  (Fi«.  HI).  Dm- 
ilriiiiui  „iil,im„ali.*  di.icolnr  (Fit.  \{))  (rax 
ffh'l'n,,,  (Fit'.  .'Wi,  Frahmila  „r.;ir,i  (Fi'k  38) 
M/<v/„  ,/,;/„,,  iFitf.  0.1).  ,„„|  flolann,.  ../.Ilanl 
IriK.  4i). 

III.     T/n:  ,./„..,,  /„./„,/,,,  ,/,„,,,  ^„,.,,.,^,  ,^^,^^_ 
nll,,„f,l,n,l.r  ,m,,„,rti,„t^)  llml  „ri,e  from  Ihr 
"hole  .urM'r  „f  ,!„■  npiir  ,>„,,ill.,  niul,  Ihn, 
'■>//,.  r  mm-  l,„r,mh  „n,l  fnllnu-  th,-  cmrmr  .rail 
••J  Ih.  n„hall   or  th.,!  prornd    l„  „  ..traiyhhr 
hn,  „„hl  Ihey  Umch  ior  „r„rly  r.;,rh)  th,-  p,,,!,- 
nor    .urjmr   of  Ihv    /,„..    ,,n„n,ll„    ,„„r    it, 
"I'K'lor      |„  „„.,,  in>,a„,.,.-.  IImt.-  is  Irvs  than 
■'-I.- l..nKt  I,  l,..|  »..,-„  1 1,..  ,«.,„.„  ,,.„„i„„|,„„, 
llx-    .-MS  rai.Mil,..     T..   tlii,  ,.|a.H.s  l„.I,m^'  ll„. 
|wft.  ns   .)f   llinnido    nislini    (Fijf  71)     / r„ 
'■".v,v./„  ,„;■,,,„  (Kij,.  .,.5).  (■,„„„„,,;,„  rervc'olor 
*!•.„'.  7.J).  Munu.  poh,,jl.,lto.  ^Fi«,  7i).  .s>,„,„. 
Uuxadratu.   ,Fi«.04,.   .V„«,/,„r„   ,.y,„„„,V,„ 
1 1- IK.  7^5).  .iramid...  />■,•,/',„(  Fii:.  ;l«),  .l/./,TV.r 
'';',"""//'     <Fi„.  47.    ami    Col.rnU    histrio.nn, 

Th."„-  arc  many   s,„.,  i,-s   v.ho.s,.    in^ctcns 
••••fipy     a     position     intrrnicliat,.     t„.lw,.,.M 
<l.-.ssn.,n,l(|assJII,  an,l«l„VI,  ar,.,.oMs,.- 
'l•K■»tly.  not  .asy  ,o  piac...     <)ftlios,.thatar.- 
f>K«n..l  m  tl„.  text  may  1...  .n.-ntion.-.l  Rhnm. 
phutn.hwmafu.  (Fi^.  ti7). OH, tetrax  (FiK  4«) 
JMocopu.,  major   (Fig.   68),   rhalacrocor,u 
rnrho  (t,f,.  51 ).  rv.r,./.,  ror«r  ( Fiff.  7B),  rv„/»r»v 
><ym,li.-<  (FiK.  09).  Pllan,m,hrl.;„„„.  ( Fi« 
<0)  and  <  iiridma  rrisfa/ii  (Fi'.'.  2."}) 
^V<7//,.  „.m-y?/.r,..v.     .\s  previously  stat.-.l 
the    neurilenm.a.    „r    nervr-shoath.'    of    the 
optiens  is  in  many  Uir.ls,  a.s  .K.asionallv  in 
Alan,  eont,nu...l   info   the   retinal   snl.stanee 
These  nerve-fil.res  are  easily  seen  in  the  avian 
fundus   u^en   v.ewe.l    with   the    ophthahno- 
scope   althouRh  ,n  preserved  eyeballs  thev  /.re 
invisible  to  the  naked  eve. 


TIIK   niNDirs  0<  ILr  OF   HIHDS 


!••  M.n.e  .MManee,  they  radiate  from  the 
iM-rve-hea,!  a,  whili.h.  thrt-ad-like  ravs  in 
xUi  U  a   f,„|„„„  ,„   ,„  ,.„^.,.^  ,,_^,  ^|^^|-  ^^^  ^^ 

wule  ar.a  nhout  the  optie  enlranre.  This 
eon. I.l.on  is  „,.|l  shown  in  T„r,l„.  n,.r„l„ 
x'\u  '"V"-  ■V"!/../..*.*  Wr«/„.,  ,|.|a,,. 
.\I.IUI,  KhamphiiMiiD  IitiikiIi,^  (I'Inle  XI  VI) 
I'l'ijmti,  Mn,„ll,„  (IMate  XXIII).  and  V.,/- 
niiUfHluH  aliituliiriiiM  i  Plate  XXXVi. 

A-.  a  rule,  however,  the  i.vianVund.is  i,  fr.e 
;,  "'".'*■  '"/'■'■  '•'••"■ents;  in  all  prol.al.ilil v 
th.-y  mfrfere  to  son.e  sli„ht  extent  will, 
K'Meral  retinal  vision  an.l  are  ,on>e.,„enllv 
al.sent  in  those  Keiiera  re,|uiri,iK  the  most 
:""'*■  ^•'=""'  l'"«'-r^-  They  are  few  in  num- 
l«>r  or  are  entirely  al.sent  ii.  .\i„hi  Mirds.  and 
m  sneh  repreM.ntative  s,M.<.ies  as  <;,,„„/„,, 
WW,,.,  ,  Mate),  XXXn  r.,.uarn..  orrU,i. 
1 1  late  nil.  Il„h,ul„.  l,„c,H-rph„h,..  (|'lale 
XXXIII)     and     lihiuorhitu^    j„hnlu.     (|«late 

They  are  short  or  inroiispiViiens  i,,  .ill  ih,. 
|.earim.te  l.irds,  so  far  examined,  inelu.lin« 
Ih.-  rinamou  (Plate  V)  as  well  as  in 
^yrl,corar  mp-llcorox  (IMate    XX),  Crox   „/,.- 

Vn,         .";;/,"•    ^'""-"'>   /"■"">""•'•"    (I'iate 
*  III  1  -iniil  haliwrorornxcnrho  ( I'late  \XVM| ). 


E.  Photography  of  the  Fundus  Oculi  in 
Living  Birds 

Mmi.v  attempts  have  I.een   mad.,  to  photo- 
graph   th,'  f,„„l„,  ocli  throu,jh   the  pupil   i„ 
l»-ing    sul,j,.<.ts  -to    eombine,    as    i|     u.r,. 
ph..toKraj)liy   with  ophthalmoseopv.     If  t|,is 
•sehenu.  IS  ever  put  into  pr.icH.al 'operation, 
t-s|M.emlly  If  It  l.e  fo„nd  possible  to  ph.,t.,«ra,,li 
ta-  eyeKroiin.1  in  its  natural  colors  so  that 
th.-  negative  .-an  b,.  repr.jdue.-.l  and  ,>iib|ish,.d 
a  K'n-at  advance   will   l,c  made  over  th.-  r.-' 
.stricte,!   (lH.,.,„ise  slow  and  expensive)   plan 
p.r   force   n.lopted    by   the   writer.     I'hotoir- 
raph.v  of  the  colorcl  .lefails  of  the  fim.lus 
W..UM  render  unnecessary  either  th,-  ex,,ert 
ophthalmologist  or  the  trained  artist,   while 
he  number  of  avian   l.ackKroun.ls  exnlor,-d 
by  such  exact  methcJs  woul.l  s,.on  be  count,-<l 
by  .undreds  where  they  are  now  retfistercl  b^• 
units.     Moreover,    a.s    the    ophthalmom.pi'c 
picture  IS  to  a  certain  extent  .lifTerentlv  inter- 
preted,  and   correspondingly   described    and 


^\\'>'^^^t«JSStS«F?/'7CliS:^.-  i-i**  '""i^f 


^•3.::'''"i:«^?Lrtr^:,.^::^ir/«rj^iia^^ 


<)PIITIIAI,M()S("()I»Y  OF  TIIK   Kl'NDI'fi   t\    11\IS<,    lUKHS 


«• 


V'\H.  (Ml. 
Amunii  PmtuI  (CArywrfu  omajoniVa). 


Viii.  e». 


Kiff.  61. 
Lcner  Sulphur-rrestrd  Cockatoo  (Variaua  gaieriia). 


FiK.  64. 
Block  Hornbill  {SpagnUiinui  iidruliii). 


fig-  6«'  Fig.  6.5. 

Kskspo  or  Owl  Parrot  (Stringopt  habropHltu) .  Nightjar  {C,, primulgui  'ur„,,e„^). 

Diagranu  of  the  Pecten  *i  seen  by  the  OphtbalmoKope  in  Various  Species  of  Birds 


^5?SS!!^B?!^!?^yS 


i. 


46 


THE   FUNDUS  OCULI  OF  BIRDS 


Fig.  6«. 
European  Cuckoo  (Cunlut  canoru^). 


Rg.  67. 
Sulphur-b««ted  Toucan  («Aam;,Aa^«  Z,^, 


'tu). 


Fig.  68. 
Great  Spotted  Woodpecker  (Dend, 


roeoptu  major) 
Diagrams  of  the  Pecten 


Fig.  89. 
Gila  Woodpecker  \Cen,uru,  (Melanerpes)  uropy^U]. 


Pig.  70. 
Derby  TjTant  (PUangw,  derbianut). 


Fig.  71. 
Chimney  Swallow  {Birundo  rurticn) 
-n  by  the  Ophthalmoscope  in  Various  Specie,  of  BiHs. 


f 


OPHTHALMOSCOPY  OF  THE  FUNDUS  IN  LIVING  BIRDS 


47 


Fig.  7«. 
American  Mocking  Bird  (Jtfimiw  pnlyglottos). 


Fig.  74. 
Blue  Jay  (CyanociOa  cristata). 


Fig.  78. 
American  Bunting  (Cyanospiza  rerticalor). 


a 
3 


Fig-  '''■*•  Fig.  76. 

Law  Bird  of  Paradise  {Parotia  lawit).  European  Raven  (Conus  eorax). 

Diagrams  of  tlie  Pecten  as  seen  by  the  Ophthalmoscope  in  Various  Species  of  Birds. 


48 


F)i<turo,l  hy  different  ol.servers,  un  aocurnte 
photographi,.  reproduction  i.  nuich  to  1„. 
di'sirod. 

rrol.al.ly  tl,e  inv,.nl,.r  who  lias  cnie  nenr- 
«-st    this  ideal   is  W„l(f  tMonahhI.  f.  Augen- 
linlL,  p.   447,   Oct.,   Xov..    1907)   of  Berlin, 
who  has  done  niu.li  in  the  photo^raphv  of  the 
human  fundus.     II,.  „,,„i,.  „„,  „f  ,,;,.  |j^,,,j 
furnished  I.y  the  Z.iss  projection  apparatus, 
the  etferent  rays  i.eini;  reflected  into  the  eve 
IIirouRh   half  the  puj.!!,  l,y  „  s,H-ciallv  con- 
trive.1  .Mirror.     The  efferent  rays  pas.s;.,!  ,.ut 
thn.uKh  the  ,.lher  half  of  the  puj.il  and  were 
foc'usse.!  in  a  photographic  canuTa      A  circh- 
of  the  fundus  al.out  10  mm.  is  thus  illuminated 
at   cue  tune  and   the  resulting  picture— of 
c..urse  in  Rra.v-  tones  -    is  magnified  fn.m  thr    ■ 
to  four  dianulers.     The  re<,uired  exi„.sure  is 
less  than  one-thirtieth  of  a  second.    The  prints 
showed  the  optic  entrance,  the  retinal  vessels 


THE  FUNDUS  OCULI  OF  BIRDS 


and  other  gross  .letails  of  tlie  eye-groun<l  but 
lacked  that  .lefinition  without  which  fundus 
reproductions  are  of  little  practical  value. 

Niimilaled  I.y  these  experiments  of  Wolff 
ai'd  by  the  experience  of  Dimmer,  Thorner 
ami  Xeiihaiis,  the  writer,  in  conjunction  with 
l^r.  tarl  Brown  of  Chicago  and  other  exp.-rls 
has  endeavored  to  s,.lve  the  problem  botli  ..f 
onhnary    and    chronio-photography    of    the 
avian    fundus.     It    must    be   confessed    that 
nothing  .satisfactory  has  come  of  these  efforts, 
nor  of  th<'  corresponding  attempts,  referr.>d' 
l<>  on  p.  61,  to  photograph  the  eveground  of 
prepared     specimen.s.     The    main     difficulty 
(without  entering  into  the  details  of  the  fail- 
ures) in  all  the.se  instances  lies  in  the  present 
impossibility  of  focussing  clearly  at  the  same 
instant  all  the  points  on  such  a  concavitv  as 
the   interior   of  the   eyeball   presents,   either 
in  Its  pn.1t  mortem  or  its  living  state. 


Chapter  VII 

MACROSCOPIC  APPEARANCES  OF  THE  FUNDUS  OCULI  OF 
BIRDS  IN  PREPARED  SPECLMENS 


This  .sul)jcft  lias  to  some  extent  been  dis- 
cussed in  Chapters  IV  and  IX.  As  previous- 
ly stated,  the  actual  appearance,  arrangement 
and  relations  of  the  organs  in  the  Hird's 
fundus  —  pecten,  retina,  optic  nerve,  choroi<l 
and  choroidal  bloodvessels,  macular  regions 
(areas  of  distinct  vision) — can  be  readily  i)er- 
ceived  in  properly  |)reserved  eyeballs.  Im- 
mersed in  Perenyi's  (Itiid  and  a  series  of 
alcohols  and  otherwise  carefully  j)repared,  an 
equatorial  section  of  an  avian  globe  furnishes 
material  for  a  satisfactory  macroscopic  study 
of  many  of  the  parts  in  the  interior  of  the  eye. 
The  gross  relations  of  these  i)arts  in  typical 
birds  are  seen  in  Figs.  1,  5,  0,  7,  and  11. 

The  Pecten  is  probably  always  somewhat 
shrunken  and  more  or  less  displaced  even  in 
the  freshest  and  best  i)reserved  spec'iniens; 
so  that  allowance  must  be  made  (in  examining 
prepared  material)  for  that  fact.  This  is  the 
reason,  perhaps,  that  Aptcryx  was  for  several 
generations  credited  with  absence  of  a  pecten, 
until  Lindsay  Johnson  proved  its  presence  in 
that  bird.  The  peculiar  construction  of  the 
small  marsupium  in  the  Kiwi  not  only  made 
it  easy  of  reduction  in  volume  but  it  was  also 
decidedly  bleached  by  the  alcohol  in  which  the 
(old)  material  was  inmiersed  for  a  long  period 
before  it  was  made  the  subject  of  that  naked- 
eye  examination  that  led  to  the  original 
error  of  observation. 

The  i)ecten  varies  in  shape  and  size,  as  well 
as  in  the  number  and  the  character  of  the 
folds  of  ti.ssue  that  compose  it,  according  to 
the  genus' to  which  the  bird  belongs.  Indeed, 
such  a  striking  and  varied  picture  does  the 
pecten  exhibit,  both  when  seen  with  the  oph- 
thalmoscope during  life  and  in  prepared  niac- 


ro.scopical  and  microscopical  specimens  after 
death,  that  one  might  almost  recognize  the  spe- 
cies by  studying  this  organ  and  its  relations  to 
oilier  parts  of  a  biril's  fuiulus.  In  the  accom- 
panying text  are  a  number  of  drawings  of  the 
avian  jHrten  as  seen  in  prepared  eyeballs. 

That  the  human  liyahUI  arlcnj  oj  fetal  life 

a  vcstigal  [X'cten  .seems  almost  self-evident. 
N'o  one  who  has  examined  a  persistent  hyaloid 
artery  and  its  branches,  particularly  if  he  has 
been  fortunate  enough  to  see  the  vessels 
carrying  blood  to  and  from  their  termination 
in  the  vitreous,  can  fail  to  be  reminded  of  the 
structures  that  occur  normally  in  some  mam- 
malian, most  reptilian,  and  all  avian  eyes. 
This  arrangement  surely  carries  us  back  in 
fetal  evolution  to  tho.se  sauropsidian  ances- 
tors who  have  left  their  mark  on  our  cm- 
bryology. 

.Attention  may  be  especially  drawn  to  the 
pecten  of  the  American  Coot  (Fulica  ameri- 
cana).  consisting  of  15  double  folds.  It  shows 
in  a  remarkable  and  unusual  fashion  their 
fan-like  arrangement,  especially  at  the  free, 
upper  margin  of  the  organ;  it  is  there  firmly 
attached  to  the  fine  vitreous  proces.ses  and 
the  hyaloid  membrane.    See  Fig.  84. 

In  (Jadow's  contribution  to  Bronn's  Tier- 
Reich  a  list  of  the  number  of  convolutions  in 
certain  Birds  is  given,  and  reference  is  made 
to  an  attempted  classification  of  Aves  based 
upon  it. 

The  op/i'c  disc,  viewed  macroseopically,  is 
generally  seen  as  an  oval,  ovoid,  sometimes 
almost  round,  white  or  yellowish-white  area 
largely  ob.scured  by  its  union  with  the  base  of 
the  pecten.  Its  long  diameter  is  generally 
from   two   to   three   times   its   width. 


[40] 


ii 


50 


THE  FUNDUS  OCULI  OF  BIRDS 


Fig.  77. 

Nubian  Ostrich 
(Struthio  canulut)  XS. 


Fig.  78. 

^rn^t.ineU  Tinamou 
(Rhyru  noiiu  rufetceru)  x  10. 


Fig.  80.  *---.,__ 

British  Wood  Pigeon  (CAumba  palumhus)  xlO. 


Fig.  81. 
Wonga  Wonga  Dove  (Leucoiarcia  pwala)  x  10. 


Fig.  79.         -., 

Valley  Partridge  or  Quail  (l^HoHy.  californicu.  Fig.  82 

rallicola)  xl6.  . 

Pigeon  GuiUemot  (Cepphus  columba)  X9 
Wa,  View  of  the  Pecten  in  the  P^pared  Eyes  o,  Certain  Species  of  Birds. 


*" m- irriiK  ^^ 


Mwvt-ir* 


i..*'.w .  i'l: 


•fsr.TSrif 


»f3!^»^^!CI 


FUNDUS  OCULI  OF  BIRDS  IN  PREPARED  SPECIMENS 


51 


3 


Fig.  83. 
European  Crested  Grebe  (Podicipei  eruUUiu)  X 12. 


Fig.  84. 
American  Coot  (Fulica  americana)  Xli. 


Fig.  85. 
Dark-bodies  Shear-water  (Pt^ffiniu  griteua)  X9. 


Fig.  8a. 
Herring  GuU  {Lanu  argentalut)  x7.5. 


Fig.  87. 
Greater  Yellow  Legs  (Totanua  melanoleuciu)  XU. 


Fig.  88. 
Hudsonian  Curlew  {Xumeniut  hudsonietu)  X 18. 


Lateral  View  of  the  Fecten  in  the  Prepared  Eyes  of  Certain  Species  of  Birds. 


59 


THE  FUNDUS  OCULI  OF  BIRDS 


FiR.  <H. 

BI«ck-cro«-„e<l  Night  Heron  (Xyeticorax  nyclicorax 
nceriua)  xO. 


Fig.  80. 
Black-bellied  Plover  (Squatarola  ijuatarola)  X9. 


Fig.  90. 
Great  Bustard  (0/w  tarda)  XS}^. 


Fig.  91. 
American  Bittern  (Biiaurui  lentiginosu,)  x8. 


Fig.  9S. 
lesser  Snow  Gooae  {Chen  hyperboreiu)  x9. 


Fig.  94. 

Common  (Old  World)  Flamingo  (PhomkopUrxu 
roteiu)  X8. 


Uteral  View  of  the  Pecten  in  the  Prepared  Eye.  of  Certain  Species  of  Birds. 


^ssaK^cji  ».'mraKvr.«xisr7BiBui'aFHK:^ 


FUNDUS  OCULI  OF  BIRDS  IN  PREPARED  SPECIMENS 


58 


i 


Fi)?.  9j. 
Brandt  Cormorant  {PhalacrHcorax  pfnicUlatita)  X9. 


Fig.  96. 
Tawny  Owl  (,S\fmium  allien)  x7. 


Fig.  97. 
European  Bam  Owl  (Strix  flammta)  X9. 


Fig.  98. 

Greater  Sulpliur-tresled 
Cockatoo  {Cacatua  gederila)  X9. 


Common  (British)  Kingfisher 
{Alcedo  upida)  X 18. 


Fig.  100. 
Common  Hoopoe  (Upupa  epopn). 


Lateral  View  of  the  Pecten  in  the  Prepared  Eyes  of  Certain  Species  of  Birds. 


«4 


THE  FUNDUS  OCUU  OF  BIRDS 


Pig.  101. 
Anna  Hummingbird  (Cciypu  anna)  X81. 


Fig.  loi.      '-  ..^ 

Yellow-billed  Cuckoo 
(Coeeyzut  americaniu)  x  18. 


Fig.  103. 
Red-headed  Woodpecker  (Melanerpe.  erytk^;,^, 


-). 


Mr.  104. 
Hcd-shafted  Flicker  (ColapUi 


meruaniu). 


Fig.  105. 
Western  Mockingbird  (ifm„  poly,u>Uo,  UucopUru.). 


Uteral  View  of  the  Pecten  in  the  Prepared  Eyes  of 


Fig.  106. 
Bluebird  (Sia/ta  rialU)  X18. 
Certain  Spedea  of  Birds. 


Fiff.  107. 
California  Shrike  (Laniua  ludotieianut  gambeli). 


FUNDUS  OCULI  OF  BIHDS  I\  PREPARED  SPECIMENS  55 

The  Retina  iiiiii  the  towels  nj  the  chormd  are 
prncticftlly  invisible  in  the  ,.yes  of  birds  viewed 
niHcroscopicttlly  a  few  minutes  after  death. 
However,  when  treated  with  Pcrenyi's  fluid 
and  otlier  preservatives  or  espeeially  in  ease  of 
sueressful  carotid  injections,  the  <horoi(hd 
bhiodvesseis  and  tissues  beeoiae  more  opaijue 
or  at  least  more  translucent  and  may  then  be 
studied  with  success.  Doubtless  the  upli- 
flialmoseope  gives  us  the  one  U-sl  means  of 
seeing  these  tissues  as  they  exist  during  life, 
but  both  methods,  supplemented  by  the  mi- 
croscope, arc  needed  for  a  complete  study  of 
them  in  all  their  relation.^.  Very  little  light  is 
thrown  on  these  (juestions  by  naked-eye  ob- 
servations of  the  choroidal  vessels,  although  in 
some  birds,  esiwcially  when  injections  of  car- 
mine have  lieen  mnde,  they  are  quite  evitient. 
Serial  sections,  in  conjunction  with  the  use  of 
the  ophthalmoscope,  afford  the  best  means 
of  studying  these  fundal  vessels. 

The  pigment  deposits  and  other  histological 
elements  in  the  choroid  and  retina  —  espe- 
cially in  the  former  —  that  combine  to  nuike 
or  modify  the  general  coloration  of  the  fundus 
oculi  are  best  seen  with  the  ophthalmoscoix-; 
prepared  specimens  furnish  but  slight  indi- 
cations of  these.  Differences  of  level,  as  in 
■■•cular  areas,  are,  however,  well  shown 
niacin.  ^„^Ically. 

Areas  of  Distinct  Vision.  As  a  result  of 
t  le  investigations  of  Slonaker  and  the  writer 
i  may  be  said  of  Birds  with  but  a  single 
i  jvea  that  this  sensitive  area  is  gen-^ rally 
:^laced  about  the  center  of  the  retina,  slightly 
above  and  towards  the  nasal  aspect  of  the 
optic  nerve  entrance.  This  observation  is 
practically  illustrated  in  a  number  of  pictures 
reproduced  in  this  work  from  the  drawings  of 
Kennedy  and  the  paintings  of  Head.  See, 
for  example,  the  drawings  of  the  fundus  views 
o{  Sialia  sialis  (Fig.  140),  Conus  americuniis 
(Fig.  142)  and  Nycticorax  nycticonix  (Fig.  129), 
in  which  a  single,  deep,  well-defined  fovea  is 
present. 

An  exception  to  the  rule  of  the  nasal  posi- 
tion of  the  single  fovea?  and  macular  regions  is 
noticeable  in  the  Owls.  These  birds  possess 
a  single,  deep  fovea  encircled  by  a  round, 
sharply   defined   area  located  above  and  on 


Fig.  lOH. 
Ameriran  Crow  (Comu  americaniu) . 


Fig.  109. 
Steller  Jay  {Cyanocitta  lUUeri)  x  U. 


Lateral  View  of  the  Pecten  in  the  Prepared  Eyes  of 
Certain  Species  of  Birds. 


S6 


II..-  Innporal  si.lo  „f  tlu-  optic-  .ii«..  „„  e,„,„„,.. 
..  whul.  M  ,„,.,. ,r...l  i„  .s>«,«,„  nluro  (hL. 
Ui)  Hii.l  .s/r,j-  Jlammi;,  {Vig.  Hi)  Tlii»  ,," 
rm.«,M„„|  d.,^.lv  „,,,,r„„,.,„,,  „„.  ,,i,„,,„|,,^ 
•"."M.  ..•  of  M.„;  i,,.,.,.,,  „,..  ,.,„,,,  „^,.„,^ 
<'f  Mr.«.f..rnu-s  r,-s.-,nl,l..s  th,-  hun».„  .-vi- 
""-■;'•  <I..mI.v  tlmn  ,lo.-s  any  ..ih.-r  ..r.l.r      ' 

II..-  rW»,V/  i.  Ht-en  ...M.r.,s,..,,,i,,,||v  ,.,H  „ 
'lark  l.a,ktfr..un.|  for  tl,.-  In.n.li,c,.„t,  or  oi.lv 
PHrlm  y  v.Ml,|..r..(i„„:i„,l..,..|.  ,l.,.,,„|„r,„i„;, 

|.ic-l,..-,-s  .,f  tl...  l.inj-,  f,„„,y,  .^  ,,,^^^,,^.  ^,^,||^ 
'■"•"•.I  l.v  this  .k-eply  piK„,,„i,.,l  o^.tar  t„„i.. 
with  .Is  rich  vascular  supply. 

Ax   notcl   i„   nuxptvr  Vill.   domotivaU,,,, 
l.n..Ks  about  diaiiKos  in  <.ll  the  fun.lal  tiss.„.s 
•iNWally   tissue  .l.-Kc..,.ration.  if  not   actual 
<l.«.'as.-.     Hen...  «e  6n.l   that  (iailin*  pos.s«..s.s 
very  shallow  or  .loiihtful  f.,ven-.     The  writer 
has   coiieer..e.i    hiu.s«-!f  lillh-   with    Imrnvar.l 
fowls     hut    Slonaker   has   shown    that    whi!.- 
f  olumlm  l,nu  domcMica,  still  r.-tains  a  n.,.,liu,i. 
fovea  surrounded  l.y  „  w,-l|..iefiu,.,l  macular 
>irva    Mvlaujn,  galloparo  ..n.l  Xumida  pmlur- 
on,    hav..    very    shallow    area-   ceulraU:.     As 
state,!  elsewhere.  s.,„.e  Birds  have  no  macular 
n-Kion  demonst rable  by  t \w  naked  ev.-.    lUdlu.', 
domesneu.     U   example,    has   an 'extremely 
doubt  ul  „v,.a.   while  Anscr  donu,tiru.  an.l 
Anai  boxchas  donuMicus,  in  a.ldition  to  a  very 
shallow  macular  region,  exhibit   a  band-like 
area  extending  horizontally  across  the  retina. 
Ihe  hitter  device  probably  enables  the  bird 
to   w.don   the  hmits  of  his  fiel.l  of  distinct 
vision  (especially  while  feeding)  without  being 
"I'hged  to  move  the  whole  head.     This  c.iri 
ous  provision  is  mo«.  clearly  shown  in  the 
Iting-.Nec-k    Plover    who.se    fundus    shows    a 
very    distinct    band-like    area     that    passes 
obliquely    acros.s    the    retina.     A    dark    line 
I'ke  a  trough  or  gutter,  appears  to  the  nake.l 
eye  ...  preserve.1  specimens  to  exten.i  abnost 
the  full  length   of  the  band.      Sl.>nake       x- 
nnned  thi.s  area  microscopically  but  could  tind 
no  trough-hke  depression. 

Oval,  ovoid,  circular  or  ribbon-like  areas 
are  as  a  rule,  readily  traced  in  the  gray' 
smooth  retinal  tissues,  although  both  the 
microscope  and  ophthalmoscopt-  may  be 
needed,  as  i„  the  Flamingo  and  some  of  the 


THE  FUNDI.    (K  ULI  OF  IHHDS 


t.olhnaceous  bir.ls.  a.s  a  suppl.-m.-nt  to  macro- 
Mopic  .„.,,H..iion  to  ,Wi.|,.  th.-  pr.„.„,.,.  or 
otlier«,«-  of  u  ma.ular  region  or  of  ai.v  of 
■  ts  con.,H.n..nts.  Tl..-  lin.its  of  H...  n,i,nd 
'wm/ ,,„.„  often  call  f..r  th.-se  aids;  in.|.....l  it 
-na.v  be  sa..l  that  m.  exph.rali.m  of  an  avian 
fun. his  shouM  be  r,,^„r,|,.,,  „,  ,,,„„,,,,.,,.  ,^^^,., 

"II  th.-se  r.-.|uirements  are  met.  .\reas  of 
acute  v.sion.  in  pr.pan-,1  material.  app,.ar  I., 
Ik-  whit.-r  ..r  l.-ss  gray  than  i!,.-  surronn.ling 
retina;  th.-r.-  is  i.ot,  h.nvever.  a  ^harp  .IcKni- 
"'"  1"  ll.e  nake.1  .-y...  or  even  wh.n  ..bs.-rve.l 
l-.v  II..-  h.-lp  .,f  a  magnifying  hns.  but  the  tis- 
SU.-S  of  th,-  «r.«.  c-ntraUs  sha.h-  olf  an,l  grn,h.. 
ally  1)1.-11,1  with  lu.-  i)erinia,iilar  tissues. 

It  must  not  Ih-  assum,-,!  that  becaiis,-  ,„. 
"-ntral  area  of  .listinct  vision  is  ,li.scover.-.| 
macr,)sc,)pically  that  it  .hx-s  n.)t  exist.  .So.ne 
".acular  r,-gions  are  so  shallow  an.l  so  slightly 
<htr.-rentiat.-,l  from  the  neighboring  tissues 
tliat  ,)i.ly  the  microseojH>  can  settle  the  .lues- 
tion  of  their  .-xistence. 

The  .-xacl  character  an.l  visual  purpose  of 
these  retinal  ban.l-like  areas  (sonietim.-s  also 
visib  e  to  th.-  ..phthalmoscojH.)  await  further 
histological  imestigation. 

Birds  of  pr.-y  as  w,-ll  as  the  swift  iliers  show 
the  best  mark,-,l  aii,l  th,-  gr,-al,..,t  variety  of 
"'aciilr  r,.gioiis.  A  ty,,ical  instan.v  Is  m-,-,, 
m  the  Sparrow  Hawk.  In  this  h  each 
fumlus  presents  a  wel)-n.arked  for-  ^mlu 
and  Jmtu  Umpnralii,  connected  bv  .  short 
band-like  iirea. 

Tl ..  naml  fovea  is  invariably  the  d.-eper  an,l 
sharjM-r  ,if  the  two.  and  probably  is  us.-.l  when 
•lisunct  sight  and  i.intx-uhr  vision ar- require,! 
It  i.s  surroundcl  by  a  large,  macular  an-a  au,l 
IS  situated  about  the  cent,-r  of  the  retina. 

Ihe  temporal  Jorea  h  shallower,  is  encircl,-,l 
I'.v  smaller  area  and  is  placed  near  Ihe 
IK-nphery  of  the  retina  lower  than  the  nasal 
fovea  but  about  the  same  distance  from  Ihe 
optic  papilla.  This  foveal  region  hohls  about 
the  same  r,-lativc  position  in  the  fundus  as 
the  .smgle  fovea  of  the  Owl  while  the  fovea 
nwiaiis  stands  i..  the  same  relation  as  that 
occupied  by  the  Blue-Bird  and  the  I{obin 

Of  the  swift  fliers  the  Terns  and  the  Swnl- 
ows  present  much  the  same  foveal  and  ban.l- 
hke  sensitive  regions  as  the  Hawks;  in  other 


FUNDUS  iKVLl  OF  BIRDS   I\   PREPARED  SPECIMENS 


47 


Fig.  1 10.    Example  of  the  First  Type  of  Central  VUual  Area-  in  Birds,    The  Amacular  Fundus  of  the 
Califurnia  \'alley  Quail  (Lophortur  californiciu  vallicola)   X 18. 


m 


Fig.  111.    Example  of  the  Second  Type  of  Central  Visual /Vre«  in  Birds.    The  Nasal  Monomacular 
Funduj  of  the  Steller  Jay  {CyanocUta  lUUeri)  x  1«. 


48 


THE  Fvsms  ornj  of  birds 


KiKlW      ^'-^    '•"f.lHThir,ITy,..„f<V,,,ralVisuulAr..«.i„I,irds      Th.  T 

Fundu,  of  the  K,,.,,....  „,,.,  o,,  t^^lS^.J^J"'"'"'  ' 


Monomacular 


RgllS.     K'-n-Ple  of  the  Fourth  Type  of  Central  Visual  Are»  in  Bird.     Th,  «•         ,     ^ 

the  British  King&her  (A^i^;!'^'    ^'  ^"^"'"  ^^'1'"  "' 


'i^ 


Frxni  s  (Hvu  UK  niKDs  in  prkpared  spe(  [mens 


worda  the  diiipoititiim  of  the  nr«iis  for  Bcutr 
vUion  n»niinn'<  this  furin  in  Hir<N  ilial  likt- 
fb«'ir  pn-y  on  Ihr  win«  or  l.y  (liirtiii«  upon  il 
fn)ni  a  diiituncc. 

A  Clauiflcation  of  Areas  of  Distinct  Vision 
in  Birds 
From  tlu'  forcKoiiijj  ii  nmy  !«•  coticliiili'il 
that  then-  an-  at  least  six  nrritnutinents  of 
these  nnvM,  ntid  ron«'<|iiiritly  six  forni>i  of 
appiii-iiliM  for  senirinn  ihhIi'  <  y.  si^hi  in  l.irds. 
IVm-  may  lie  clan-tified  as  follows: 

I.  The  amariilar  fiDidii.i,  in  which,  as  in 
the  California  Valley  (^lail  (s<v  Fij;.  UOi, 
there  is  to  !>.■  s«H'n  neither  with  the  ophtliiil- 
inoseoiH-  nor  in  pn-served  material  any  iniliea- 
tion  of  a  eentral  niaeidar  region i  rather  a  rare 
cittsst.  It  is  only  1  v  a  inierosinpical  exan ma- 
tion  of  serial  seeti  'ns  that  one  sees  Ih,  liis- 
lolo^ie  elements  indicative  of  an  area  of 
vision  more  s|Hrialize<l  for  ilislinet  visualiza- 
tion than  the  surroiindinR  ntina.  Such  fundi 
are  rare,  and  are  fontid,  for  example,  in  a 
few  domestic  birds.  Slonaker  <liseovered  a 
shallow  and  ill-define<l  eentral  area  in  the 
Turkey  (Mvlaiyrin  yullopnro)  and  the  Guinea 
Ilcn  (Sumidiii  piirhernni);  also  "a  very 
sliKl>t  thickening,"  instead  of  a  fovea,  in  the 
Cook   {(lallim  domeatirus), 

8.  The  naml  mniumHindar  fundus,  situated 
in  the  centre  of  the  retina,  is  found  in  the 
majority  of  birds.  An  example  is  shown  in  a 
drawiiiffof  the  eyeground  of  the  Steller  Jay  (s«-e 
Fig.  111).  A.s  a  rule,  it  is  best  demonstrat' d 
niHcroscopically,  although  even  a  cursory  ex- 
amination of  the  colortMl  plates  in  this  work 
will  reveal  numerous  examples  of  this  form  of 
fundus  when  viewed  ophthahnoscopically. 

3.  The  temporal  monomundar  fundus  is 
found  almost  exclusively  in  the  Owls.  An 
example  of  this  form  is  seen  in  the  Euro|Han 
Barn  Owl  (Fig.  112);  indeed  in  all  the  Strigi- 
fornies  whose  fundi  are  pictured  or  ilescribed 
in  this  nionograjjh. 

4.  The  bimw  ular  fundus,  in  which  there 
are  two  maculse,  generally  a  deeply  marked 
an.l  principal  na.sal  region  and  a  subsidiary 
temporal  area.  See  Fig.  ll.*},  representing  a 
macroscopic  view  of  the  (preserved  eyeball) 
fundus  of  the  Belted  Kingfisher. 


50 

There  ri>  two  Mdivarielies  of  this  fundus; 
(<l)  certain  eyes  of  re^idar  form  in  which  the 
nasal  macular  rtyiim  s  well  develo|).-d  and 
the  fovea  is  deep  .md  ^hiirply  .lelined,  as  in 
Alredi),  SIrrnn  and  Tarhyrinrhi:  (b)  in  bird" 
with  eyes  of  if  egular  sha|H'.  exhibiting  u 
deeiKT  temiurrnl  fovea  and  Iwlter  marked 
macular  regi...  These  are  found  in  llie 
Hawks   espi'ii.ily. 

.'».  A  liiind-lik,-  cnlral  arrn  with  which  i:» 
almost  iii\ariat)ly  ass(H-iated  a  w.  Il-de(ined 
fovea  or  ni.iiul.i.  To  this  form  of  avian  baek- 
grouiid  Hi.  writer  has  given  the  name  i'h/i//(|- 
murnhtr*  fundus.  A«  an  example,  sec  Fig. 
1 II,  showing  a  iiiacroscopical  view  of  the  eye- 
ground  IN  the  (Jreiitcr  Yellow-legs  iTolnuus 
m<'lnni<lcuiHs).  In  this  <  lass  the  band  in- 
'loses,  in  some  part  of  its  course,  the  single 
fovea  which  in  its  turn  is  found  on  the  nasal 
side  of  the  fundus. 

<i.  Finally,  in  some  ;ivian  Kackgrounils 
t  her  ,ire  two  macular  n  [lions,  either  juiurd  Id  ,,r 
assoriaird  with  the  liaud-Uk,-  area,  to  which  the 
name  infulaliimaruUir  fundus  has  Keen  given 
by  tla-  writer.  .\n  ocular  background  of  this 
description  is  seen  in  the  Common  Flamingo. 
See  Fig.  1  Iv  .  There  are  at  least  two  varieties 
of  this  for  n. 

The  Sparrow  Hawk  (FdAo  sparrerius)  and 
Bull!  ■orfalis  furnish  examples  of  form  (a)  — 
a  w  ll-cictined  nasal  macula  with  a  det-p  fovea 
situ;  1.(1  nvar  the  centre  of  the  rctirui  and  a 
shallow  liiough  easily  demonstrable  lemporal 
macula.  Hi-'  two  joined  by  a  -furl  ribbon- 
like are.\.  Vl,,.  hand  area  does  <n>i  extend 
beyoiii     eit'i.T   macular   region. 

In  .secoi;  '.  :.rm  (i),  represented  by  the  Tern 
{Sterna  hiii:  daK  the  band-like  an'a  encloses 
a  nisiil  macula  while  a  second  (temporal) 
macular  region  lies  abov.  and  apart  from 
tlie.se. 

Fven  n  -light  acquaintaiK .  .vith  the  fundi 
(k'dorum  f  th^  comparati\.l;  few  Birds  .so 
far  examined  ;,iiows  not  only  numerous  types 
of  ar.w  centrales,  but  a  still  greater  variety  in 
their  size,  shape  and  appc.irance,  both  mae- 
roscopical  and  ophthalinosc(.-)ieal.  These  are 
mos-  distinctly  marked  m  th.  prepared  six'ci- 
mens.  Some  Birds  exhibit  ..  large,  circular 
'Infula,  a  band  or  rilii  on. 


60 


THE  FU>a)US  OCULI  OF  BIRDS 


Fig.  1 14.     Example  of  the  Fifth  Type  of  Central  Visual  .Wa-  i„  Bird,     The  I„f  I 

of  the  Greater  Yellow-Ieg,  iToU.n7ZZteJ)      ^"'"''""-"'"  "-d- 


Fig.  US.    Example  of  the  Sixth  Type  of  Central  Vi, 


of  the  Common  Old-woHrFl^So^Tj::.^?''  '"'"''""-"'"  ^undu 


I  roteut). 


^ 


FUNDUS  OCULI  OF   BIRDS  IN    PREPARED  SPECIMENS 


61 


area  —  single  or  Jouhlo.  sonictinies  nssoeiali-d 
with  ii  Ijaiiii  ari'ii,  soniotiiiifs  not— with  clearly 
<)utline<l  margins  antl  a  deep  fovea  anil  dis- 
tinct foveola.  In  otiiers  the  fovea  is  shallow 
and  the  niaenlar  borders  arc  with  iliflionlty 
differentiated  from  the  fundal  retina. 

Photography  of  the  Fundus  Oculi  in 
Prepared  Eyeballs 
Attempts  similar  to  those  of  Wolff  and 
others,  mentioned  in  Chapter  VI,  to  photo- 
graph  the  interior  of  the  i>osterior  half  of  the 
eye  hav«'  t)een  ma<le  with  some  siiceess  in  the 
ease  of  prepared  eyes.  The  difflcnilii's  that 
surround  these  attempts.  althoii<;h  fewer  than 
with  the  living  subject,  are  as  yet  unsur- 
mounted  so  far  as  minute  and  e.\act  funilal 
details  —  the  chief  object  to  be  attained  — 
are  concerned.  Pliotography  furnishing  a 
clear  and  sharp  definition  of  small  objects 
arrays  '  at  various  points  in  one  concave  sur- 
face is  as  yet  impossible  —  hence  the  blurred 
apiH-arance  of  pictur.  of  the  vcrte))rate  eye- 
ground  so  far  publi>..,d.  Even  the  best  of 
these — the  enlarged  stereoscopic  ph'>to- 
graphs  that  illustrate  Arthur  Thomson's 
Anatomy  of  the  Human  Eye  (London,  1912), 
the  carefully  prepared  original  photographs 
in  the  beautiful  atlas  of  Frit.sch,  and  the 
stereographs  of  Ceorge  Dixon  —  hold  out 
little  hope  that  similar  processes  may  be  of 
use  iti  depicting  avian  eyegrounds.  Only 
the  laborious  pen  and  brush  of  the  careful 
and  competent  artist-ophthalmoscopist  can 
so  far  be  depended  upon  to  depict  the  mac- 


roscopic  appearances   of   these   complicated 
tissue  arrangements. 

R.  II.  Elliot  (The  Lancet,  p.  830,  Nov.  11, 
1910)  has  develo|K>d  a  nu'Uiod  of  photograph- 
ing i)repared  eye  specimens  of  which  the 
writer  has  had  no  (jcrsonal  experience,  but 
which  he  l)elieves  may  Ix'  of  value  to  the 
investigator.  Elliot  regards  th<-  following 
points  of  importance:  The  photograph  must 
be  taken  in  water,  without  the  intervention  of 
glass  or  other  similar  material.  The  source 
of  light  must  be  good  and  even.  The  camera 
nuist  be  placed  vertically  above  the  object 
so  as  to  avoid  reflections.  The  obji>ct  of  the 
photograph  nuist  be  placed  so  that  its  image 
will  occupy  the  center  of  the  plate,  and  a 
method  of  adjustment  should  be  available  to 
.secure  this  end  with  a  minimum  of  incon- 
vcniena*.  A  simple  arrangement  is  neces- 
sary to  fix  the  eye  in  position  during  the 
whole  period  of  exposure.  To  save  unneces- 
sary retouching  the  object  should  be  photo- 
graphed lying  on  a  dark  and  uniform  surface 
to  obviate  the  background  disturbing  the 
attention  of  those  viewing  the  picture.  Care 
should  be  exercised  in  the  choice  of  a  camera 
and  exposure  periods  must  l)c  carefully 
studied.  For  the  making  of  lantern-slides 
the  contact  method  was  recomniendetl,  and 
attention  was  directed  to  the  following  points: 
correct  exposure;  the  preparation  of  plates 
for  exposure;  development  and  fixation  of 
the  slides;  the  dr,ving  of  the  plates;  and  the 
reduction,  intensification  and  varnishing  of 
slides. 


I 


I 


Chapter  VIli 

EFFECTS  OF  DOMESTICATION  AND  OTHER  ARVORMat 

INFLUENCES  ON  THE  FUNDUS  OCULI  OF 

WILD  SPECIES  OF  BIRDS 


As  noted  ,n  Chapter  III  the  eyes  of  only 
healthy  in.hvi.hials  and  (as  far  as  couhl  l,e 
ascerlame,!)  of  normal  wil.l  siMvies  have  Invn 
chosen  for  the  purpos.-s  of  this  research.     In 
praet.ee,  however,  this  is  not  as  easv  a  task  as 
tirst  .-.ppears,  s,„ce  it  is  on  occasions  diffieult 
to  .leei.le  l.y  „ny  or  nil  of  the  three  principal 
means  of  mvestigation  -  the  ophthalmoscope 
in  l.vinf-speeiniens.  the  microscope  and  naked 
eye   m   preserved   globes  -  whether  a  given 
con,htion  IS  normal  or  abnormal,  congenital 
or    acquired.     The    writer's    observations    of 
he  eyes  of  both  domestic  and  wild  birds  leads 
hm.   to   b,-l,eve   that  dmnes'icaiion  of   Birds 
winch  generally   means  a  radical   departure 
from  their  natural  food,  exercise,  manner  of 
raising  their  young,  use  of  their  various  or- 
gans (eyes  ineluded)  and  above  all  the  effects 
of  confinenjent  per  se,  is  the  principal  cause  of 
lie  anomalies  seen  in  the  fundi  of  caged  or 
barnyar.1   species.     This   difficulty   in   deter- 
niimng  the  exact  character  of  tissue  altera- 
lons  IS  all  the  greater  when  the  suspected 
fundus  change  occurs  in  both  eyes  and  the 
organs  are  not  available  for  macroscopic  and 
microsco;,.c  examination.     For  instance,  the 
eyeground  of  the  .Spoonbill   (Plate  XXV)  is 
shown   with  a  curious  (and  unusual)  linear 
stripe  running  parallel  and  clo.se  to  the  optic 
<;>(•.     This  may  be  an  abnormal  fundus  con- 
dition although  the  weight  of  evidence  leans 
tJie  other  way. 

SnHr.nal  bird,,  when  caged,  appear  to  Ik,- 
ospecUly  atfcHed  by  "Zoo"  conditions. 
Ihe  (  apr.mulgi.h.c.  as  well  as  the  Strigi- 
fornies  for  .-xaniple.  are  liable  to  accpiire 
choroidal  diseases. 

16«] 


nh.Ie   e.xam.n.ng   a   number   of  common 
Screech  Owls,  the  writer  found  one  individual, 
about  five  years  old  and  three  years  in  captiv- 
ity,  that   showed   the  followi-  g  conditions: 
J^eft  eye;    usual  Owl   fundu,;    well   marked 
disseminated  choroiditis,  affecting  the  nasal 
aspect  of  the  background  more  than  the  tem- 
pora  .    The  choroidal  vessels  show  through  a 
number   of  atrophic  areas.     Usual   pigment 
spots  smaller  than  normal.  almo.st  punctate. 
Right  fundus:  the  general  appearance  on  this 
side  is  of  a  striped  gray,  very  much  like  the 
warp  and  woof  of  some  fabrics,  or  like  the  begin- 
ning  choroidal  atrophy  of  myopia.    In  other 
respects  the  right  fundus  resembles  the  left 

Mr.  Head  informs  me  that  in  examining 
with  the  mirror  a  Bluebird  (Sialia  sialis)  in 
captivity  seven  years,  the  vitreous  humour 
was  found  to  be  quite  dull  and  foggy  and  the 
fundus  showed  spots  of  an  orange-r^d  color. 
This  was  very  likely  a  diseased  condition,  as 
ttie  other  eye  had  a  cataract  in  it. 

The  writer  has  examined  with  the  ophthal- 
moscope the  eyes  of   a  number  of   Turkey 
\  ultures  (CaM«r/..  aura),  practically  domestic 
animals  in  many  American  towns,  and  found 
few  of  them  healthy.     In  one  case  the  bird 
had  cataract  in  each  eye.     In  another  there 
was   beginning  central   opacification   of  the 
lens  in  the  left  eye;  the  same  condition  more 
advanced  in  the  right.    A  third  had  no  len- 
ticular changes,  but  owing  to  a  suspicion  that 
he  fundus  findings  might  not  be  those  of  a 
healthy  individual  the  findings  were  not  in- 
cluded in  the  list  described  in  Chapter  IX. 
Ihe  following  are  the  notes  of  this  examina- 
tion:   Left  fundus;  general  coloration  steel 


EFFECTS  OF  DOMESTICATION  ON  THE  FUNDUS  OCULI 


gray.  Resembles  the  Bald  Eagle.  Pecten 
large  and  apparently  reaches  posterior  part  of 
lens.  Optic  nerve  entrance  entirely  obscured 
and  ojjtie  nerve  fibres  are  persistent  at  teni- 
porid  margin  of  the  disc.  Uetinal  reflexes 
very  distinct.  At  the  upper  and  temporal 
edge  of  the  disc  the  white  border  of  papilla 
shows  quite  distinctly.  Pecten  very  black 
and  in  no  part  translucent;  lies  in  well  defined 
coil-like  folds.  No  definite  visual  areas  can 
be  dilfcrentiated  from  the  general  fundus. 
Fundus  'granular'  in  places.  The  refrac- 
tion slightly  hyperopic. 

Beginning  with  his  experience  as  a  student 
in  the  Thierartzneischule  of  the  University  of 
Berlin  in  18S8,  the  writer  has  examined  the 
eyes  of  many  barnyard  fowls,  to  find  in  them  a 
great  variation  in  the  fundu.s  appearances  even 
of  the  same  species.  The  following  few  de- 
scriptions from  notebooks  will  suffice  to  illus- 
trate this  point: 

Bantam  cock  {Callus  domesticus).  Fun- 
dus examination;  direct,  with  electric  ophthal- 
moscope. Both  backgrounds  the  same.  The 
whole  eyeground  is  of  a  uniform  'pepper  and 
salt'  and  granular  variety  — the  'pepper' 
predominating.  The  macular  region  shows 
quite  plainly,  the  fovea  being  represented  by  a 
single  star-like  deposit  which  looks  exactly 
like  (and  may  be)  a  crystal  of  cholesterin. 
The  disc  is  a  long  oval,  almost  but  not  en- 
tirely covered  by  the  pecten  at  each  side  but 


(S3 

quite  clear  at  either  end.  The  pecten  changes 
size  and  position  under  the  examination  but 
not  so  (luickly  as  in  the  Crow,  for  cx.-.mple. 

Large  and  mature  'spc-ckled  hen,"  with  a 
light,  brick-rcd  iris.  Kept  in  laboratorv  of 
St.  Luke's  IIosi)ital  as  a  source  of  pure  aVian 
blood.  The  observations  on  the  bantam 
rooster  just  detailed  almost  entirely  coincide 
with  the  findings  in  this  bird,  except  that  no 
single  stellate  formation  in  the  macular  region 
was  noticed.  Skiascopy  and  pupil  reflexes 
alnjost  the  same.  There  was  no  noticeable 
astigmatism  developed  in  either. 

A  great  variety  of  fundal  pictures  —  nor- 
mal and   abnormal  —  are  presented  by  our 
Domestic  Pigeons.    The  following  are  notes 
on  the  fundi  of  the  Homing  or  Homer  Pigeon: 
The  background  is  readily  seen  in  all  these 
domestic  Pigeons.     It  bears  a  close  resem- 
blance to  that  of  the  common  Hen,  except 
that  the  macular  region  is  better  defined  in 
the   Pigeon.    The  sprinkling  of  fine,  dark- 
brown  pigment  over  a  reddish  background, 
interrupted  here  and  there  with  colored  points, 
generally    yellowish    and    glittering,    giving 
the   whole  a   uniform   appearance   like   fine 
'mixed  tweed"  cloth  seen  from  a  distance  of 
a  few  feet,  is  very  characteristic  of  this  class 
of   fundi.    The   pecten   is   relatively   small, 
clubbed,   spiral,    black-brown   and   prevents 
one  from  seeing  more  than  a  third  of  the 
ovate  disc. 


m 


CiLVPTER  IX 


That  one  .n;.y  properly  answer  many  questions 
wivolv,..!  in  the  anatomy  and  physiolo^'v  of  the 
■rnporlani  organs  and  tissues  that  constitute 
111.-  eyegroumi  in  Vertebrates  it  is  neeessarv  to 
.•onsider  not  only  the  ophthalmoseopie.  l.ut'lhe 
maeroseopie  and,  in  some  instances,  the  nr 
croscop.e  findings.     Although   none  of  tliese 
methods  of  research  has  as  yet  been  .arried  out 
with  any  approaeli  to  completeness  vet  the  1ns- 
tology  of  the  retina  and  other  visual'organs  has 
l.ccn  satisfactorily  studied  in  .Man.  and  a  few 
otiicr  species  of  Vertehratse.  by  Cajal.  Greeff 
and    others.     Little  attention   has,  however 
been  pai.l  to  the  other  two  forms  of  investiga- 
tion, that  IS  to  avian  ophthalmoscopvorto  what 
may  ..e  termed  avian  ophthalmamacroscopy. 

OpJithalmoscopy  is,  in  effect,  a  demonstra- 
tion of  the  actual  (comparative)  size  and  -da- 
tive position  of  the  principal  parts  -  nerves, 
bloodvessels,  [oil  droplet  (.')]  dots,  organs  of 
special  sense-as  well  as  the  actual  coloration 
of  the  fun.lus  oculi  of  the  living  Bird.    Macro- 
-scopy.  on  the  other  hand,  reveals  some  .letaiis 
of  the  Bird  s  eyeground  not  apparent  or  onlv 
famtly  apparent  to  tl.  „  .ophthalmoscope.    For 
sample,  the  extent  and  other  exact  relations 
of  some  of  the  areas  of  acute  vision,  as  well 
as  definite,  literal  views  of  the  pecten,  are 
better  determined  by  naked-eye  examinations 
of  prepared  specimens  than  by  viewing  them 
tlirough  the  pupil  of  animate  species  •    To 


an7t'i.i!;."\""'-  '"'r-""  ""^  '"'"'"^  '"  ""^  black 
and   «l„tc.  ,lraw,ng,s   (to  indicate   the   maorosoopical 

erely  the  ar.,.,f.s  device  to  depict  the'concavity  ol 
he  evehall,  elevafon  of  parts,  etc..  and  have  no.Kng 
to  do  with  the  fundal  dot,  and  other  coloration  so  w"ll 
shown  in  the  colored  plates. 


[64) 


his  may  be  added,  ns  elsewhere  pointcl  out. 
that  in  certain  instances  the  fine  anntomv  an.l 
exact  relation  .  of  certain  organs  an.l  tissues  of 
the  background  of  the  Bird's  eye  can  b,-  <leter- 
m.„e,i  only  by  a  microscopical  examination  of 
stained  and  injected  sections  of  the  parts 

The  following  siK-cies  (healthy  adults)  have 
been  examined  either  with  the  ophthal- 
moscope „r  by  insfK-ction  of  prepared  eve- 
'•■'lls.  or  by  both  methods.  I„  a  number. 
al>..,  the  eyes  have  been  .sectioned  and  ex- 
amined microscopically.  These  findings  have 
been  mostly  pictured  in  the  text  or  by  ap- 
pended colored  plates,  and  will  now  be 
described. 

A.    RATITAE 

Stnithioniformes 
Nii-an   or     Northern    Ostrich.      Slruthio 

view).  The  black  and  white  drawing  of  this 
fundus  show.s  a  large,  regularly  oval  papilla 
spr.nkle<l  with  pigmented  dots  and  circled  by 
a  well-defined  border. 

The  foreshortene.1  view  of  the  -.ectcn  gives 
one  the  impression  of  an  octopus-like  figure 
.vmg  upon  and  almost  covering  the  surface  of 
the  optic  disc,  which  is  plainly  visible  beneath 
and  sprinkled  with  pigment  dots.  There  are 
readily  counted  twenty-four  pectinate  con- 
volutions (12  double  folds)  that  meet  abo-,  - 
and  are  joined  to  an  irregularly  ovoid  bodv  - 
-he  crest  or  free  margin  of  the  marsupiun,  - 

tZTS\Z  "  '"''  "^  purse-string  action. 
The  folds  of  the  pecten  are  extremely  thin  and 
en  irely  unlike  the  great  majoritv  of  the  con- 
volutions in  carinatc  birds. 


K^at. 


THE   FIXDIS   APPEAHAXf'ES   IN    VAHIOlS 


OHDEHS  OF  BIRDS  65 


n  wl 


m 


F'K-  in.      Rufous  Tinamou  (Rhyncotus  n<fe<<cem)  x  10. 
Macroscopic  Appearances  of  the  Fundus  Oculi  in  the  Preserved  Eyes  of  Bird.. 


iftii: : 


66 


THE  FUNDUS  OTUIJ  OF  BIRDS 


A  loiiR,  uniform  band  „f  two  .lark  lines 
.•n.l.winK  a  I.h.m.I.t  wliii,.  I,.„„)  runs  almost 
horizontally  across  the  fuiuhis  above  the 
optic  disc.  About  the  middle  point  of  the 
l>an.l  (above  the  disc  and  towards  tlie  nasal 
asiKvt  of  the  fundus)  is  a  round  ilepression 
(O.  l>lack  in  the  center  and  surrounded  by  two 
indistinct,  pigmented  semicircles,  made' by  a 
wi.leninR  of  the  parallel  lines  that  enclose  the 
fundal  band. 

The  extended  major  axis  of  the  optic 
entrance  oval  describes  an  anj-le  of  almost 
45°  with  the  inferior  border  of  the  retinal 
band. 

This  angle  the  writer  has  called  the  ivfula- 
papillary  angle,  from  infula,  a  band,  and  pa- 
pilla, the  optic  disc. 

I'late  I,  page  121,  gives  a  verj-  good 
Idea  of  the  ophthalmoscopic  apjK-aranees  in 
this  .species.  It  represents  tlie  eyeground  as 
■seen  in  specimens  examined  l)y  Head  in  the 
r.ardeus  of  the  Hritish  Zoological  Society  and 
l)y  the  writer  in  a  young  male  adult  living  in 
the  open  and  un.ler  ideal  conditions  on  the 
Cawston  Ostrich  Farm  near  San  Diego,  Cali- 
fornia. 

The  general  color  of  the  eyeground  is  dull 
red,  varied  by  a  uniform  sprinkling  of  lighter 
red,    round    dots    and    gray    granules.    The 
lower  half  of  the  fundus  appears  somewhat 
grayer  in  tone  than  the  upper  sectors.    This 
appearance  is  probably  due  to  the  numerous 
opaque    nerve-fibres    that    extend    from    all 
sides  of  the  papilla  as  a  center  across  the  fun- 
dus to  the  periphery  of  the  ocular  background. 
The  red  coloration  of  the  fundus  is  seen  to  be 
more  intense  towards  the  upper  half  of  the 
eyeground.     The  optic  nerve-entrance  is  very 
broad,  oval  in  shape,  and  its  contour  resembles 
that  of  Rhea  and  the  Tinamous.    The  mar- 
gins of  the  nerve-head  are  very  white  and  it 
is  possible  with  the  mirror  to  'see  all  around 
the  pecten.    The  centre  of  the  disc,  including 
the  parts  near  the    root    of   the    jiecten    is 
.slipplea  with  minute,   brown  pigment  dots, 
like  black  pepper  grains. 

The  pecten  projK-r  rises  from  the  nervehead 
much  like  the  same  organ  in  the  Tinamou 
and  presents,  ophthalmoscopically,  the  ap- 
pearance of  a  number  of  dull,  dark,  sepia- 


brown  tubercles.  It  does  not  project  far 
forwar.1  into  the  vitreous  cavity,  while  its 
outlines  and  contour  may  be  <listinguishe.l 
both  above  and  below  the  disc.  The  jwctin- 
ate  niargins  are  formed  of  round  or  ovoid  pro- 
je.-tions.  These  nodular  masses  also  app<Nir 
to  constitute  the  body  of  the  pecten. 

Tlie  macula  is  situated  about  as  it  is  in 
Rliea;  it  is  not  very  striking  in  appearance, 
and  takes  the  form  of  a  creseenlic  arrange- 
ment of  minute,  gray  dots.  It  is  seen  towards 
the  nasal  side  of  the  di.sc  near  its  upix>r  end, 
and  is  not  surrounded  by  the  closed  reflex- 
ring  noticed  in  so  many  avian  fundi. 

Rheifonnes 
American     OsTnicii.      Rhea     americana. 
J-or  an  exact  reproduction   in  color  of  the 
ocular  background  of  this  bird  see  Plate  II 
page   HI.   which  shows  the  left  eye;  erect 
image. 

The  coloration  of  the  fundus  as  a  whole  is 
buff,  merging  into  dull  red  at  the  periphery 
It  is  stippled  all  over  with  minute  dots  of 
a  lighter  tint,  and  much  resembles  the  fun- 
dus appearances  of  the  Tinamou  shown  in 
Plate  V. 

The  optic  disc  appears  to  be  a  broad  oval, 
made  up  of  white  and  coarse  nerve  bundles 
that  exhibit  a  faintly  defined,  fringe-like  mar- 
gin all  around  its  periphery.  Radiating  for  a 
distance  of  about  two  disc-breadths  across 
the  fundus  are  a  few.  dull-gray,  opaque  nerve 
tibres  that  finally  disappear  into  the  back- 
ground. 

The  macvla  is  situated  slightly  above  and 
to  the  nasal  side  of  the  optic  papilla.  It  is 
somewhat  grayer  than  the  surrounding  eye- 
ground;  above,  towards  the  outer  side  and 
below  the  fovea,  are  a  few  pale,  bright-green 
reflex  lines. 

The  pectm  is  a  massive  organ  with  saw-like 
margins,  the  serrations  being  of  a  lighter 
brown  than  the  central  body.  The  lower 
part  of  the  pecten  is  somewhat  club-shaped, 
and  comes  well  forward  toward  the  posterior 
capsule  of  the  lens.  Between  the  projecUng 
teeth  of  the  pectinate  serrations  may  be  seen 
a  slight  stippling  of  pigment-like  black  pepper 
grains. 


t:i 


THE  FUNDUS  APPEAUANCES  IN  VARIOUS  ORDERS  OF  BIRDS 


Casuariiformes 

Wkmtkhmav       Tahsowauy.  Casuariiin 

o<-eipU(ili.i.  Tlu-  colored  drawiiiK  shown  on 
Plate  III,  pii^je  IW,  is  iritcniled  to  reproduce 
nil  ophtiialnioscopic  view  of  the  right  eye  by 
the  erect  image.  Two  hirds  (four  eyes) 
furnished  almost  identical  pictures. 

The  fawn-colored  njegrimnd  is  covered  with 
a  minute,  silver-gray  .stipple,  in  the  form  of 
fine,  short  lines  with  their  long  n.xes  running 
in  u  vertical  direction.  As  these  dotted  lines 
a|)i)roach  the  macular  region  they  become 
more  and  more  ((jnvergent  until  they  form  a 
l)rilliant  cluster  at  the  fovea.  There  is  no 
visible  line  of  demarcation  or  retlex  ring 
separating  this  area  from  the  general  fundus 
iirea.  There  are  no  visible  choroidal  blood 
vessels  or  opacpie  nerve  fibres. 

The  opiic  disc  is  long  and  boat-shaped, 
with  a  reddish,  apparently  concave  centre. 
It  is  uniformly  sprinkled  with  darker  red 
tlots,  which,  as  they  approach  the  margin 
of  the  papilla,  are  more  clo.sely  packed,  and 
give  the  apijcarance  of  a  shadow  cast  all 
about  the  inner  edge  of  the  disc.  The 
margins  of  the  nerve-head  are  distinctly 
white,  but  they  have  not  the  "fibrous" 
appearance  seen  in  most  avian  backgrounds. 
The  chocolate-brown  peden,  much  broader 
at  its  base  than  at  the  apex,  resembles  a 
corkscrew,  its  lateral  elevation  being  not 
unlike  a  cockscomb,  with  its  six  serrations 
rounded  off  at  the  apex.  Two  central  .serra- 
tions come  well  forward   towards  the  lens. 

Apterygifonnes 
Mantell  Apteryx.  Apteryx  manlelli. 
In  July,  1914,  the  writer  examined  a  Mantell 
Apteryx  in  the  London  Zoo.  The  animal 
was  12  years  old  and  probably  had  monocu- 
lar vision.  The  keeper  said  that  (in  daytime 
especially)  the  bird  had  poor  eyesight  for 
both  distance  and  near.  The  bird's  re- 
fraction was  by  skiascopy  myopic  (about 
1.50  D.)  in  either  eye.  The  fundus  appear- 
ances arc  exactly  as  Head  has  depicted 
them  in  his  drawing  (Plate  IV).  In  this 
fundus  picture  the  macular  region  is  plainly 
visible;  and  the  pccten  comes  well  forward  and 
is  also  easily  seen.    The  ocular  I     k-ground  is 


67 

uniformly  orange-red,  somewhat  mollled  with 
brown.  The  brilliant,  white,  round  disc  is  sur- 
rounded by  short,  opaque  nerve-fibre  layers, 
not  entirely  covered  by  the  fenestrated  base 
of  the  long,  large  and  conical  peclni,  whose 
pointed  end  reaches  almost  I  o  the  lens.  There 
are  no  signs  of  choroidal  bloodvessels. 

Tinamiformes 
RiiFoi-.s  TiNAMotJ.  Rliijnrotii.i  rufincenn. 
(Figs.  117  and  78).  A  macroscopic  picture 
of  the  hack-ground  shows  a  slight  and  rather 
uniform  pigmentation,  darker  towards  the 
jH'riphery. 

The  long,  narrow  comb-like  pevlen  some- 
what resembles  w  hen  seen  from  before  back- 
wards, a  small  crayfish.  It  is  made  up  of 
from  48  to  .50  convolutions,  the  dorsal  crest 
forming  an  irregular  triaigle  with  a  short 
.spine  projecting  from  its  inferior  end. 

The  macula  is  plainly  marked  above  and 
on  the  nasal  .side  of  the  pecteii,  about  half  a 
disc-length  from  the  anterior  terminal  of  the 
papilla. 

AIautineta  Tinamou.  Calodroma  clcgans. 
A  picture  of  the  left  ocular  fundus  (by  the 
erect  method)  is  furnished  by  Plata  \  . 
page  125.  This  taxonomically  interesting 
spi'eies  presents  a  background  whose  colora- 
tion is,  in  the  main,  a  deep  gray,  the  lower 
half  merging  into  dull  orange.  The  whole 
of  the  fundi  is  covered  by  a  collection  of 
tiny  dots  packed  closely  together.  In  the 
upper  half  of  the  field  they  are  white,  but 
from  the  region  of  the  disc  and  downwards 
they  become  a  dull  orange  color.  Crossing 
the  fundus  and  running  vertically  on  either 
side  of  the  papilla  are  several  orange-red 
choroidal  capillaries. 

The  macula  appears  as  a  dull-gray  area, 
with  a  brilliant  white  central  spot  surr^  unded 
by  a  small,  pale-green,  streaked,  reflex  ring. 
It  is  plainly  visible  on  the  nasal  side  of  the 
pecten.  The  optic  nerve  entrance  is  oval 
in  shajM;  and  exceptionally  broad. 

The  mass  of  the  pecten  almost  completely 
covers  the  optic  papilla,  which  is  quite  white 
and  looks  like  a  mass  of  coarse  opaque 
nerve  fibres.  Ihe  optic  margins  are  bor- 
dered with  gray  pigment,  from  which  spring 


in' 

fi  f! 
i 

m 


68 


:'  f.-w  short  ..,mf,u,.  norve  fibres.  Tl..-  wrtrn 
"  '•''."<-»l'"'-  t'r..un.  ami  i„  ,„|,li,i„„  ,„  ;„ 
"'"«iv,.  apiH^aran.,-  is  niu.h  shorter  than 
M..-  Hamo  orKa,,  i„  n,„st  of  the  birds  oxaniin.-.l. 
All  imrts  a,„l  all  .l.-tails  of  this  ,H-clon  can  bo 
vio«...  w.th  the  mirror  without  the  least 
..Iheulty  It  .s  easy  to  see  that  it  is  fringed 
•'II  around  wth  pointed  tabs,  that  the  central 
I>->r  .on  or  r.dRo  i,.  serrated  and  that  it  ron.e. 
«■.■  1    orwar.1   towards   the  I.  n.s.     In  exan.in- 

l'rm,«h    he  unddated  pupil  the  jn-cten  seems 

I"   hi!    the  pupillarj-   area   so  that   most   of 

he   fundus  ,s  obscured   an.l   shows   through 

.e  fnuRe  about  the  papilla  a.  a  light  shines 

through   a  grating. 


THE  FUNDIS  OTILI  OF   DIHDs 


CARIXATAE 

Gallifonnes 
Yarkell  ClKA«.sow.  (rax  yUo.m.  The 
fundus  app<.„r„„ces  of  this  bir.l  are  depicted 
";  J  late  \I.  page  U5,  and  are  the  result 
"f  an  exammation  of  four  eyes  in  two  speci- 
"K-ns.  The  four  backgrounds  were  foun.l 
to  be  identical  in  all  resp<-cts. 

Thv  cyeyround  is  a  dull,  l.-aden  grav 
covered  w,th  tiny,  white  dots.  There  ar'e 
no  visible  choroidal  vessels. 

The  papilla  appears  as  a  long  oval,  whose 
central  zone  is  dull-orange  mingled  with 
■"■"ute,  dark-brown  dots.  It  also  presents 
a  marginal  fringe  of  while.  A  few  opaque 
nerve  fibres  exlen.i  on  either  si.le  of  the 
disc  across  the  fcndus,  but  for  a  short  dis- 
tance  only. 

The  peckn,  of  spiral  form,  is  colored  dark 
chocolate-brown  I,  seems  to  taper  quite 
decidedly  where  it  joins  the  disc,  and  looks 
like  the  roots  of  a  tree  at  its  distal  end, 
where  the  rootlets  bury  theniselve.  n  the 
disc.  Just  above  the  disc,  some  little  dis- 
tance to  the  nasal  side  of  the  pt>cten  is  •, 
round,  gray,  softly  outline.l  area  near  whi.i, 
IS  seen  a  well-marked  reflex  of  a  pale  blue- 
green  tone. 

Hate  VII,  page  127   depicts  an   ophthalmo- 
scopic view  of  this  species. 


The  ,-y,ground  is  .lull,  slaty  gray,  under- 
iM.ig  numlHTs  of  fine,  light-gray  dots.  These 
•lots  are  uniformly  scattere.l  over  the  fundus 
x<cpt  towards  the  uH.,al  side.  Her,-,  on  a 
level  with  the  sup..rior  en.l  of  the  optic 
"cr/e  and  ,n  the  Vlirection  of  the  macular 
area,  hey  are  brilliant  white,  are  clo.sely 
packe.1  together  and  arc  devoid  of  a  reflex- 
ring.  "* 

Kxtending  from  either  si.le  of  the  optic 
'l"<c  an.l  running  at  right  angles  to  that 
organ  are  a  few.  rather  fine,  semitranslu- 
cent  nerve  fibn-s,  which  are  lost  towards 
tne  jXTiphery. 

The  opiir  dhc,  whose  upper  en.l  is  shnpe.l 
I'ke  the  sharp  bow  of  a  boat,  app«.ars  to  be 
compose.1  .,f  a  mass  of  brilliant,  white,  .,p„nue 
nerve  fibres.  ' 

The  Kr/.«,  of  the  usual  chocolate  brown 
color,  IS  massive  and  .s.,niewhat  club-shaped 
It  extends  well  forward  towards  the  lens 
an.l  tapers  rapidly  as  it  approaches  the 
superior  end  of  the  nerve. 

C.UFOH.MA    Valley    Qvail.     LophoH„x 
cahforn.eu,  valhcola.     (Figs.  110  and  79.)    An 
cxam.nati.,,,    ..f    this    background    with    the 
nakcl  eye  discl..ses  no  vell-defincd  macular 
n-gion,  at  l.-iust  not  in  this  .specimen;  it  may 
.e  that  in  better  preserved  material  a  shallow 
fovea  can  be  isolate.l.     The  pccten  presents 
nterop.,stenorly    an    elongatul,   acuminate 
hgure    with    30    convolutions,    or    15    folds 
regularly  .lisposcd  on  either  .si.le  .,f  „  straight' 
'"ear.    m-Hlian    .rest,    that    runs    the    whole' 
length  of  the  .,D,K-r  aspect  of  the  free  bonier 
Hie   conv.ilu'  o.is    are   separate.l    at    severed 
points,  especially  near  the  mi.ldle,  so  that 
glimpses  of  the  .lotted,  whitish  opIir  ml      nr 
iH'iieath  may  be  seen. 

HAnLEy,;i.N  Qiail.  Coturnix  hislrio. 
Ihe  remarkable  fun.lus  of  this  bird,  view  , 
with  the  .,phthnlm.,sc..pt>,  is  portrav.-d  as 
•ate  \  HI,  page  127,  of  this  monogn.r.h. 
The  picture  is  the  result  .,f  an  examination 
of  several  individuals,  all  exhibiting  i.lentical 
eyegrounds. 

The  general  color  nj  the  ocular  background 
's  light  gray  .prinkl.-d  with  minute  granules 
which    give,    it    the   appearance    of   a    rough 
surface.       This     granular     surface     appears 


THE   FlNDrs  API'EAHAXCES  I.\   VAHIOl'S  ORDERS  OF   BIRDS 


(i» 


■11'' 


Fig.  119.    British  Wood  Pigeon  {Columba  palumbua)  xlO. 
Macroscopic  Appearances  of  the  Fundus  Oculi  in  the  Preserved  Eyes  of  Birds. 


70 


whi...  or  Ii,I.|  ,^„y  ^.,,.„  ,|i„,,|v  i||u„,i„„,...| 
u;    n..l..c.,...|    ,i,,.,    of   th..   ..ph,h..l„.o- 

"•'"pic  mirror. 
TIm-  ,,;,//,.  „,„,.;,,,„/     i,.,.^  , 

"''"'•.     «l...rt.    ,.o„rs...     .,,„„,,„.    ,i,,„.^      „^ 
:  ;r    '^    ''""^""1.    l-inK    lo„K   ,uu|    narrow. 

l'r..j.T  ,„«.  .s..rr„t,..l  jaws  „f  ,l,e  Swor.l  Ki,h 

tliiii,  opaciiic  iicrvf  fihr,.,. 
TIk.  /„.,./,.„  is  li«hl..r  l.rown  in  .-olor  than 

«'ll'  tl...  pap.lla.     On  ..illK-r  .si.l,.  of  il  an-  « 
<•«■    nnnnl,.   .lol.s   of   l.rown   piK„u.„|.     Tlu- 

".«.t...l,     ...Iky    n.ass    which,    however,    ox- 

""  •:  «'■"  f""*-^-'  """  11..'  vitreous  cavity 
to  the  |,oster.or  surface  of  the  hw.s.  \o 
'l.'lHul,.  ,„a,.uh,r  region  was  .liscovere.l  in  the 
various  s|)eeiMieiis  examined. 


THE   FUNDUS  OCULI  OF  DIHDS 


Columbiformes 

\Vo.n,;a       Wcncia       Dovk.       locosarcin 

^''•..'".(h,-s.ll8an.l81;n.acroseo,.ic  views.) 

lhcrel,„a,„,he,.yesof,he„Me.s,..cime„ 

.-..ne..     showed     an     unusually      smooth 

/ri'e    loiiK,    narrow    j>eHen    resemlWe.s    the 

into";;  ,  *'"  'ir'  ''*«^""'  "•"'  p-i-t« 

to    h,.  vitreous  hke  a  house-he«ti„K  ra.lia- 

t-r     v.th    ahout    19    coils,    forming    S8    (or 

...;n-)    convolutions   in   all.      The   rid,.o-like 

rest   conceals  the  up.H-r  mid.lle  line  of  the 

;■':;;""'■  ■"-'*  -l"^-''.  in  its  tum.  cntirdv 

'l.>cures  a  v.ew  of  ,he  oplie  entrance.     Th'e 

lower  free   horder   "f  the  niarsupium  appears 

us  a  hroad  parallelogram  covered  with  ,r 

"'-"t    ,'ra,ns    conlra.sting   sharply    with    the 

-.perior   ..nd.  whi,.h   comes   gradually  to   a 

rounded  point.  .»    i"   « 

^^Jliere  is  no  nrU-defi^ed  macular  or  Joreal 

As    shown    in    I'lufe  IX,    page   129,    the 
"cular  background  of  thi.s  .secies  pr^ln 
when   exannned    by    the   ophthalnmsc";^  'a 
"  f°  .';  gray  tint.     White  dots,  lighting  up 
Hie  fundus,  are  scattered  over  the  entire  fold 
A  few  choroidal  capillaries  are  to  be  seen 


Iho  op^,cd^»c  forms  «  |„„„  „v„|;  it  „,,. 

l-ars  as, f,t  wen-  compos..]  Ufa  collection 
"'wh.lehl.r..s.  and  the..  s...m  bunched  to- 

P-.t.n.     Op»,,ne    nerve    (ibn-s    radiate   from 

crcumfereme  of  the  p,.pilh,  while  s^-v- 

•ral    „ran«...r..d    (choroidal)    ve.ss..|s.    inter- 

J-rse,!  with  pigment  dots,  run  o„  either  si.le 

The    prr/.«    „p,H.ars    as    an    exceptiom.llv 

"'K.    corrugated,    dark-br.mn    ma.ss.     .S..„ 

through   the  mirror  from  above  it  has  the 

a|.|K-aran«.  of  a  piece  of  tarred  ro,H.. 

^hv    macular   area    is    scrn    to    the    inner 

nd_     The    .sheen    of    the    pale-grcvn    reflex 

hat  plays  about  it  when  illuminated  In-  the 

hght     of     the     ophth«lmosco,H.     loots'  like 

^Icred  .si  k.     The  fovea  ha.s  the  apix-aranc e 

froM  tT'/"^'"  fl"«'.  -""-thing  like  that 

^o..»'>""-eye  lantern  sc^nclcse  at  hand. 
Only  one  macula  can  be  s»-en 

bRrm,,   Wooo  PioEoN.    Volumba  palum- 

The  /^r  "V"'' '"=""—»»-  views.) 
riie  i„c^,ro«„J  of  thi,  .peeies  shows  a, 
elongated,  pointed,  ovoid  pecten,  made  up  of 
l„r.  I  '^*""«  P''™'i«n.''  (about  at  in  numb<.r) 
bod  .l",,"^'''"  nPf-r  margin.  The  main 
tjodj    of  the  pecten  is  not  conci-aled.   as   it 

above  which  has  an  abrupt  flattened  app..„r- 
2-^  Wow.    an    acute   sloping    teriniLai':;. 

A    faint    and  doubljul  foreal  dcpresHm  is 

^.dt  of  the  di.sc  m  some  specimens  examined 
but  this  area  does  not  show  plainly  in  the 
individual  here  pictured. 

The  ophthalmoscopic  appearances  in  this 
si>ec.es  are  depicted  in  Plate  X.  page   W9. 
The    general    tint     of    the    ocular    back- 
ground, as  «.en  by  the  erect  image,  is  p„|e 
■slate-gray      The  eyeground  is  co '  ed   T 
very  small,  dull-white  dots  .so  that  the  whole 
fundus    presents    a    lighter    shade    of    gray 
than    It    otherwise    would.     On    the    low/r 
half  and   each   side   of   the   optic   disc   art' 
.seen  several  orange  colored  choroidal  bloo<l- 
vcssels.  which  become  more  numerous  as  one 
approaches    the    periphery.      Extending    7i 


THE  FUNDUS  APPKAHANCKS   IN    VAHIOIS  ORDERS  OF   BIRDS 


f:. 


riRht   anj{li\s  to   the   (tiipilliiry   iimrKin   im-  a 
fi'w    o|m<|uc    tH-rv*'    HI>rt"H. 

A  little  above  the  su|«Tior  eii.i  ,.f  the 
optic  iierve-hend  ami  towanU  tin-  iiiisul 
side,  is  a  small,  rouml,  apparently  somewliitt 
ciepr..s.He(J  maeular  area  of  a  cliill-Kniy  lone. 
From  its  margins  runs  a  doiiliK  row  of  tine, 
l.lue-Kreen,  translucent  lines  wliieh  form 
alioiit  it  a  broken  or  irre^ilur  rellex  rinK. 
The  bird  iK-comes  unnxiially  reslle>i  when 
the  iij{ht  from  the  oplithalinoH<<,pic  mirror 
is  fmused  on  this  part  of  the  fundus. 

(ilimpses  of  portions  of  ih,.  „ptic  dhc 
nhow  it  to  Im-  dead  whit.-,  and  it  seems  to 
have  a  fringe  of  short  6bns  of  the  same  color 
all  about  its  edges.  At  the  junction  of 
the  pecten  with  the  nervo-hcad,  i.e..  along 
the  central  area  of  the  lat»  r,  one  sees  numer- 
ous brown  pigment  dots  thai  ap|)ear  like 
small  rootlets  or  capillaries  and  give  a  reticu- 
late appearance   to  the  papilla. 

The  pecteii  itself  has  a  dark  chocolute- 
brown  color  and  a  corkscrew  contour;  it  is 
unusually  long  and  narrow,  and  its  lower 
segment  app<'ars  to  conic  well  forward 
towards  the  lens. 

ViCToHiA  CuowsKD  Pir;Kov.  Goura 
victoria.  The  fundus  oculi  of  this  sfKH-ies, 
depicted  as  Plate  XI,  page  131,  right  eye, 
erect  image,  is  of  the  usual  gray  color  seen  in 
Pigeons  and  Doves.  The  eyeground  gen- 
« rally  is  covered  with  minute  white  dots. 
On  the  upper  and  nasal  .side  of  the  fundus 
i.s  the  macula,  a  small  dull-gray  area  sur- 
rounded by  a  gray  and  green  reflex  of  small 
lines. 

The  optic  disc  is  long,  narrow,  boat-shaped 
and  a  little  rounded  at  the  upper  end.  It 
looks  ;i  it  were  rather  hollow  and  gray  in 
the  centre,  with  a  white  rim  all  around. 
A  network  of  small,  brown,  pigment  dots 
is  disposed  along  the  centre  on  either  side 
of  the  pecten;  and  some  opaque  nerve  fibres 
extend  across  the  fundus  on  all  sides  of 
the  nerve. 

The  pecten  is  of  the  usual  dark,  chocolate 
tint.  It  is  corkscrew-like  in  appearance, 
but  one  end  is  rather  club-shaped  and  looks 
as  if  it  were  covered  with  small  brown  nodules. 
This  segment  comes  well   forward   towards 


71 

the  leu-,  but  not  so  much  as  in  the  Woo<I 
PiKcon;  olherwisc  the  fundus  closely  re- 
sembles the  eyeground  of  thai  bird. 

RalUformei 

Amkiii(»\  f(K>T.  Fidica  amerirana. 
(Figs.  UO  and84.J  The  backgnmnd  of  this 
s|K'cies,  m.u  roscopicall\  considered,  shows. 
obliciuely  acp  s  the  fundus  but  not  reaching 
the  jMriphery  at  either  end,  a  "split  stick" 
figurt'-a  narrow  band  of  iinpigmtnted  ntina 
depicted  by  two  doited  lines  of  pignu-nt, 
the  line  towards  the  optic  disc  containing 
more  granules  than  the  other.  Midway 
between  thi>  tw,-  ends  of  this  figure  is  a 
circle  of  |)igment.  twice  the  width  of  the  band 
itself,  made  by  an  extension  of  the  pigmented 
borders  that  form  the  boundaries  of  the 
l>and.  In  the  exact  center  of  the  circle  is  a 
plainly  marked  pigment  dot. 

The  large,  thick  pcrttu  is  wider  at  its  middle 
than  at  either  end.  It  has  about  iH  clearly 
defined  convolutions,  or  10  double  folds. 
Uhi'n  seen  from  above  one  may  perceive 
between  the.se  plications  not  only  the  bla<k 
c«  iilral  body  of  the  pecten  but  the  papillary 
edges.  The  free  border  of  the  pecten  has  ii".. 
definit.-  k.-.l  but  the  upper  margins  of  the 
convolutions  join  to  form  a  serrated  wavy 
line  reaching  from  one  terminal  to  the 
other.  This  practically  naked,  saw-like 
crest  is  unusual  in  the  pcctens  the  writer 
has  •xamined. 

The  long  axis  of  the  papilla  prolonged 
to  nuvl  the  n-linal  band  iiiakes  with  it  an 
angle  of  about  TO',  the  inju  '  tpapillary  angle. 
Chfstei)  Coot.  Fulica  cri.ilatu  In  the 
several  s]  .ens  examined  ophthalnio- 
.scopically.  Uie  fundus  ap{)earanccs  of  this 
Australian  bird  (see  Plate  XII,  paj.'e  131) 
were  practically  itientical.  The  colored  re- 
protluctioii  presents  the  left  background  by 
the  usual  direct   i  lethod. 

The  predominant  color  of  the  eyeground 
is  dull  gray,  everywhere  sprinkled  with  mi- 
nute, white  dots  that  are  more  clearly  seen 
above  the  su{)erior  termination  of  the  optic 
nerve  and  to  the  nasal  side  of  the  pecten. 
Although  this  area  is  (judging  from  the 
effect    of    the    light    thrown    upon    various 


m-f!kv 


w 


TUF   FINDIS  (KCLI  OF   BIRDS 


Fi(?.  lil.     (iriat  Oestetl  (irelw  (,Pudicipea  crintataa)  XU. 
Macroscopic  Appearances  of  the  Funda,  Oculi  in  the  Preserved  Eyes  of  Birds. 


THE   FINDIS  AITE.VK.\N<  KS   r\   V.VKKH  s  OKt^KHS  OF   HIHI)S  73 


quattrantst  of  Ihc  fumlui  l>y  tin-  imrrori  vrr> 
iirniiitivr  lo  Mght  Iht-r*'  \*  no  ollur  ophilmi- 
IlKMM'opic  iiKlii'iition  of  a  iiia<-iiltir  rrj^imi. 

Tho  loiix  <)i>t,r  (/(.«.■  ii  while,  willi  ii  ft  w 
liny  |>i|{ni<'Mt  lUiit  nlioiil  its  nniririn--  Tin' 
IMilfu  in  li((htrr  lirowii  Ihun  in  tin-  majority 
of  liirtl^;  it  it  v«t>'  larnc  uUtm-l  liiilin); 
Ihf  ilisc  from  view  Many  o|mc|U)-  ni-rvt- 
fil)r«'»i  rmlialf  from  the  |>a|)illary  <ir«iim- 
frrftiM'  anil  rxli-nil  M-viTal  I'i  i-  lir<-ailtlis 
ac-roN.^  the  fumliis.  Owin^  tn  !,,■•  Iur(,'i'  .>«izr 
of  fhf  iMH'ten  ami  tin-  Nniall  iiii|iil  il  i>i  im- 
pos.sihli'  lo  ol)lain  a  HatiKfactoi-y  lateral  view 
of  till'  iH-elen.  wliieh  nlniosi  covers  Iht-  pupil- 
lary area  with  its  nms-.l\.-  eliil>-»lia|Mil  etui. 

Tin'    .\nicri<'an    roiii-.  hit    of    t|ui    lunl 
Fiilini  (/wrriVoMfi  -lln^a  finiiln      Inu.^l  nlfnti- 
cal,  uplithalmoM-opirall  '.uilli  tin-  ^peeirt. 

Ifkcaiia  Hail.  Aniinnln  •'pici'hu  'li,c 
ophthalmoHcopic  picture  of  liii-  (I'rd.  rrp- 
resetitinn  Iht-  riglit  eye,  it,  se,n  .i>  I  ,  i.-  Xlll. 
paK<>  \^S. 

The  eyrgTonnd  is  a  ver\  pair  iiiiifunii  ;.'ray 
stippled  with  .jarker  ^ruy  and  vliite  dol- 
thus  K'ving  the  whole  field  .1  trra'iul.ir  ap- 
pt-arancc. 

The  horizontally  oval  macular  ana  ion 
the  na.sal  aspect  near  the  up|H'r  end  of  the 
»lisf)  assumes  a  pinkish  lone.  .M  its  center 
is  a  small  pit  which,  in  the  lif;ht  of  the  mirror, 
opiH-ars  a.s  dark  gray  with  a  brilliant,  white 
central  clot.  Arountl  the  macular  ri-ffion  is 
a  pale,  hlue-ffray  reflex,  which  lo.ses  itself  in 
the  general  tone  of  the  fundus  liuf  appears 
quite  sharp  on  the  inner  side  of  the  oval 
macular  region. 

The  disc  is  a  narrow,  wJiite  oval,  whose 
major  axis  measures  about  one-third  the 
height  of  the  pecten.  .V  number  of  opa<|ue 
nerve  fibres  run  across  the  background  at 
right  angles  to  the  papilla  and  fade  into  the 
general  gray  of  the  fundus. 

The  pecten  arises  from  the  upjH'r  segment 
of  the  disc,  spreads  out  on  it  like  the  root  of 
a  tree  and  gradually  disap|>ears  into  the 
papillary  substance.  From  this  root  a  long, 
slender,  spiral  form  projects  into  the  vitreous. 
It  is  brown  in  color,  is  of  uniform  width, 
looks  like  a  corkscrew  and  extends  forwards 
and    outwards   as   far   as   the   eye   can    see, 


l<Niking  il-  if  it  were  pri'ssed  against  the  lower 
part  of  the  lehs.  The  anterior  enil  of  the 
I"'"  tell  i*  i!iM  ■h  ilarker  in  (nlor  than  it»  |)o«- 
lerior  hi.  ••   li  is  ijuile  Hut. 

The  fl        ,!•.  iH'uli  of  the  Weka    Hails   ^(}ry. 

ilnimii  Is  '(iiite  similar  to  the  iHular  ba,  k- 
grouuit  of  this  s|i>-<'imen. 

Podicipediformet 

(JllKAT         <'ltt;sT>:0  (illFUK  Pixiiripcii 

<ri.ilalii.i.  (Figs.  W|  and  H3.)  \  nnuro- 
seopie  examination  of  the  fundim  oculi  in 
this  s|M'eies  reveals  a  broad  retinal  Itand,  uni- 
form III  width,  that  extends  from  the  nasal 
[MTiphery  aenn.  the  fundus  and  is  lost  in  the 
pigment  of  the  opposite  side.  It  is  half  as 
will.'  :is  the  minor  axis  of  the  oval  dis*-  and, 
ii'niig  its  whole  length,  is  depicted  by  two 
paiallil  lines  of  pigment  dots— the  inferior 
bonier  containing  the  more  minierous  grains. 
The  nasal  half  of  the  wide  band  is  bisected 
l)y  M  narrower,  almost  linear,  ribbon  coni- 
poseil  of  minute  black  dots  that  are  most 
imnierous  at  the-  |)eriphc">  of  the  field, 
becoming  fainter  and  fa  >o>  ii-iSil  jut 
before  the  iiiaeula  is  re.u  ii  I  when  they 
clisap|H-ar  altogethei' 

\\  about  a  Ion;;  ,  I  I'.  .Ik  I;.'.  i-  fro!n 
the  superior  end  ■••  ihf  •.■■■.i-  >.;•.  'ii  its 
nasal  side-,  is  a  I  .,.  .'rc':.  '  nti'i'  pig- 
nienled.    disc-like      ■:  ■      r    ».,.,»»  ..<?ed 

within  and  some, In  -  ^  .!  ■.  ;•.  ,tiits 
of  the  retinal  bauii.      •.    i  .  „    ■     i      •■ 

central,  depressi-d  lighli/  "  i.  .,  '  (ml',; 
l>v    a    small    ring    of    pigui  m' 

The  pecten  covers  the  cjplu  i..iiance,  and 
has  the  steam  radiator-like  form  of  the 
Wonga  Dove.  However,  this  sjH'cies  ex- 
hibits ii  convolutions,  the  free  border  shows 
three  ch-finite  elevations  above  and  it  has  a 
(lov\),  opaciue  keel  to  which  all  li  double 
folds   are   firmly    united. 

The  angle  made  by  projecting  the  major 
axis  of  the  oval  optic  papilla  until  it  bisects 
the  lower  border  of  the  retinal  band,  the 
infulapapillary  angle,  is,  approximately,  70°. 

In  injected  specimens  of  this  species  (as 
well  as  occasionally  in  individuals  not  so 
treated)  the  choroidal  vessels  show  very 
plainly. 


74 


THE  FUNDUS  OCULI  OF  BIRDS 


Fig.  U3.     Pigeon  Guillemot  {Cepphiu  columba)  X9. 
Macroscopic  Appearances  oi  the  Fundus  Oculi  in  the  Preserved  Eyes  of  Birds. 


i<  .?f^.  Av^mnHTjiEBK^ffiBK^mfr  ?«MMe»Bnv>ssenwsin« 


THE  FUNDUS  APPEARANCES  IN  VARIOUS  ORDERS  OF  BIRDS 


75 


Colymbifonnes 

Pacific  liOox.  Gavia  pacifica.  Tho 
writer  has  never  been  able  to  examine  more 
than  one  individual  of  this  sjiecii •^,  or  any 
other  Diver.  He  was  obhged  to  use  the 
ophthalmoscope,  with  little  protection  from 
the  blazing  sun  of  a  Californian  noon-day, 
upon  a  recently  dead  bird.  The  examination 
was  necessarily  incomplete.  The  fundus  was 
light  gray,  dotted  over  with  dark  pigment 
granules;  the  pectcn  was  large  and  there 
was  a  well-marked  porus  opticus. 

Sphenisciformes 

Black-footed  (Cape)  Penguin.  Sphen- 
i.icu.i  demersus.  The  eyeground  of  this 
species  is  depicted  as  Plate  XIV,  on  page  133 
of  this  monograph. 

The  dominant  color  of  the  fundus  is  bright 
red  shading  to  crimson.  It  is  generally 
stippled  with  minute,  dark-red  and  orange 
dots,  much  like  grains  of  sand.  About  a 
disc-length  from  the  upper  end  of  the  optic 
disc  these  dots  become  grayish-white;  indeed, 
the  fundal  coloration  is  distinctly  gray 
towards  the  upper  half  of  the  eyegi'ound. 
In  a  region  the  same  distance  towards  the 
temporal  aspect  of  the  background  may  be 
seen  a  clu.ster  of  pinpoint,  brilliant,  white 
dots  ill  the  macular  area.  Penguins  use  the 
nictating  membrane  very  frequently  when 
light  is  thrown  on  this  part  of  the  eyeground. 

The  optic  disc  exhibits  enamel-white  edges; 
it  is  hollowed  out  in  the  centre,  like  a  sewing- 
niachine  shuttle.  Running  across  this  con- 
cavity and  at  right  angles  to  the  margin  of  the 
di.sc  one  sees  a  large  number  of  gray  fibres. 

The  pecten  lies  along  the  centre  of  the 
nerve,  where  it  is  orange-red  in  color  and 
mottled  with  minute,  brown  pigment  dots. 
The  pecten  has  the  usual  dark  chocolate- 
brown  shade.  It  is  of  spiral  form,  like  a  cork- 
screw laid  on  its  side.  A  few  slender  opaque 
nerve  fibres  are  visible  on  each  side  of  and  at 
right  angles  to  the  disc. 

Procellariifonnes 

Dark-bodied  Shearwateb.  Puffinus 
griseus.  (Figs.  122  and  85.)  The  fundus  of 
this    species,    as    seen    by    the    naked    eye, 


exhibits  a  darkly  outlined  band,  widest  at 
the  nasal  extremity  and  at  its  middle,  with 
irregularly  pigmented  borders  and  a  lighter 
center,  runs  across  the  field  of  view  from 
one  periphery  to  the  other.  Its  central 
third  is  shown  as  uncolored  except  for  a 
line  of  pigment  that  divides  it  into  two  equal 
strips — thus  constituting  a  linear  fovea,  the 
circlet  seen  in  some  other  band-like  areas 
being  absent. 

There  are  20  convolutions  in  the  rather 
short,  thick  pecten.  These  double  coils  are 
so  divided  where  they  join  the  compara- 
tively narrow  sloping  crest  that  glimpses 
may  be  had  of  the  nerve  head  below.  The 
keel  covering  the  upper  portion  of  free  border 
is  prolonged  into  a  blunt,  rounded  process, 
partly  formed  by  the  larger  and  higher 
posterior  "teeth"  or  segments  of  the  niar- 
supiiim. 

What  has  by  the  writer  been  termed  the  in- 
fulapapillary  angle  is  5o^.  This  is  made  by 
projecting  the  major  axis  of  the  papilla  to  meet 
the  lower  margin  of  the  transverse  sensitive 
area  of  acute  vision. 

Alciformes 

Pigeon  Guillemot.  Cepphus  columha. 
(Figs.  23  and  82.)  The  background  of  this 
species,  when  viewefl  maeroscopically,  re- 
veals a  narrow,  uniform,  pigmented  retinal 
band  that  stretches  across  the  field  of  view 
from  one  periphery  to  the  other.  At  a  point 
where  it  approaches  the  superior  end  of  the 
papilla  is  placed  a  circular  area  (the  fovea) 
whose  diameter  is  twice  the  width  of  the 
band. 

The  pecten  is  remarkable  in  that  it  rarely 
obscures  a  viev.-  of  th'  margins  of  the  long, 
broad,  ovoid,  optic  nerve-head,  which  has  its 
pointed  extremity  upwards.  There  are  .SO 
convolutions  in  the  pjctii'.afe  mass,  and 
occasional  views  can  be  had  of  the  papilla 
through  clefts  in  it.  The  ridge-like,  free 
border  of  the  pecten  is  linear  for  a  third 
of  its  length  below  but  follows  the  undula- 
tions of  the  convulutions  beneath  it  until 
it  reaches  its  superior  end.  The  double 
folds  in  this  organ  are  longest  and  most 
voluminous    at    their    middle,    where    the 


BHi^'BmGBx^KnKJi;ifs«ii'?jMiiJWSK«MivrKEitimrTir«aiifirHiB^ 


I  lH'fluWi'flHK13»''1KWUV 


r  :■«.,»;;;  M^iMJiiiiBifiv-ii;; 


76 


THE   FrXDlS  (K'lL,   ov  BfKDS 


Pi*-'    H4.     Ilerriiij;  f;„||  (/„ 


anis  argentatim)  X7..5. 


FiK.  l-i5.     IIuds„„ia„  <  „rlc»  ,'.V«m„„».,  /,,„!,,_  „,,^ 
Macrosoopi,.  A,.,>eara.,„.  „f  „,e  Kundu.  ...„,i  i„  t,,..  ,W .,  Kye,  of 


'Isonirus}. 


Oirda. 


^^^^^PIM 


Si 


Si?SJ^^^;fRij;::>'|-:^'S;: 


THE  FUNDUS  APPEARAxVCES  IN  VARIOUS  ORDERS  OF  BIRDS  77 


crest  or  keel  is  elevated  to  n  sharp  point, 
and  towards  which  the  olher  folds  are  in- 
clined. They  gradually  decrease  in  size 
towards  both  the  posterior  free  margin  — 
an  unusual  disposition — and  to  the  anterior 
or  superior  terminal  of  the  optic  entrance, 
in  accordance  with  the  rule. 

The  longtT  axis  of  the  disc  projected  until 
it  meets  the  retinal  hand  makes  with  the 
latter  an  infulnpapillary  angle  of  about  05°. 

I'lFKlN.  Fratcreulu  arrlica.  The  eye- 
ground  of  this  remarkable  sjjecies  is  portrayed 
as  Plate  XV,  page  135.  It  represents  the 
left  eye  as  seen  by  the  direct  ophthulnio- 
.scopic  metho<l. 

The  general  color  of  the  eyeground  is  red, 
rather  uniformly  stippled  with  small,  mixed, 
light-red  and  dark-gray  dots,  .\bove  the 
upper  end  of  the  optic  disc  and  towards  the 
temporal  .side  is  a  small,  round,  red  area  ."ur- 
rounded  by  a  pale,  light-gray  film,  shot  with 
bright  lines  on  the  outer  and  inner  margins  — 
doubtless  the  macular  region  with  its  central 
fovea.  Head  noticed  that  not  only  this  area 
but  most  of  the  upper  half  of  the  fundus  is 
very  sensitive  to  light. 

The  optir  papilla,  oblong,  narrow  and  with 
a  rounde(i  upper  extremity,  lies  low  down  in 
the  ;yeground,  while  the  |)ecten  extends  well 
forward  and  behind  the  lower  margin  of  the 
pupil.  .\  view  of  the  nerve-head  is  much 
obscured  by  the  body  of  the  massive  pecten 
which  almost  covers  it  when  seen,  as  with  the 
mirror,  from  above  downward.  The  small 
segment  visible  with  the  ophthalmoscope 
appears  not  brilliant  white  but  rather  a  bluish- 
white,  the  margins  of  the  pecten  being  covered 
with  black  pigment. 

Extending  at  right  angles  to  the  disc  on 
both  sides  are  a  few  very  fine,  gray  opaque 
nerve  fibres,  that  finally  disappear  in  the 
fundal  periphery.  The  pecten  is  of  the  usual 
chocolate-I)rown  color  and  comes  well  for- 
ward towards  the  lens,  especially  in  its  infe- 
rior aspect. 

Larifonnes 

HEnm.Nti  (liLL.  Larn.i  argentalus.  (Figs. 
124  and  86;  macroscopic  view.)  In  this 
species  the  upper  and  more  pointed  extremity 
of  the  pecten  points  slightly  to  the  temporal 


side  of  a  linear  fnrea  that  is  drawn  as  a  rather 
tiroad,  short,  retinal  band  that  skirts  the  clear 
area  and  stretches  in  a  slightly  obliiiue  direc- 
tion across  about  one-third  of  the  central 
field.  The  icneal  slit  (nearly  as  long  as  the 
optic  di.sc  is  wide)  occupies  a  widened  portion 
of  the  band-like  process  and  shows  a  line  of 
pigment  dots  along  its  upper  margin. 

The  very  broad,  long  pecten  covers  an 
equally  large  papilla.  It  has  36  thin,  leaf-like 
convolutions  which,  in  prepared  .specimens, 
do  not  obscure  the  margins  of  the  nerve-head, 
whose  canoe-shaped  outlines  are  everywhere 
visible  from  above,  except  at  the  bow  and 
stern.  The  fre(  irder,  comparatively  wid(>, 
is  deeply  i)ignieii  rd,  does  not  reach  the  supe- 
rior extremity  of  the  pecten  and  has  the 
appearance  of  an  car  of  maize.  The  medial 
and  posterior  leaflets  of  the  pecten  are  the 
longest,  only  the  anterior  five  becoming 
smaller  as  they  approach  the  upper  extremity 
of  the  papilla. 

The  infulapapillarj- angle  measures  about  60? 

The  ophthalmoxcopic  appearances  of  the 
background  are  the  same  in  both  the  European 
and  New  World  species.  A  large  number  of 
healthy  individuals  were  examined  both  by 
Mr.  Head  and  the  writer. 

The  ocular  background  of  this  bird  is  quite 
similar  to  that  of  Larus  marinus.  The 
prevailing  color  is  dull  brown,  the  upper  half 
being  interspersed  ivith  masses  of  small  gray 
dots,  that  assume  a  pink  hue  downwards 
from  the  upper  end  of  the  optic  disc.  One 
notices  in  this  region,  also,  many  dull-red, 
choroidal  capillaries  that  run  parallel  to  the 
sides  of  the  elongated  nerve-head. 

.\  little  above  the  upper  end  of  the  papilla, 
towards  its  inner  or  nasal  side,  is  the  fovea 
ccntrali.i.  a  brownish  red  dot,  in  the  centre  of 
a  rather  dull  area.  This  macular  region  is 
enclosed  by  two  clear,  bright  green  rings,  or 
rellex  circles. 

The  optic  r/i>  (papilla)  appears  to  be  made 
up  of  very  short,  brilliant  white  and  rather 
coarse  opa<|ue  nerve  fibres.  Extending  fro.n 
its  margins  are  a  few,  dull-gray,  opaciue  nerve 
fibres,  thai  radiate  from  the  elongated  papilla 
but  fade  awny  in  the  [MTiphery  of  the  back- 
ground. 


.,'•-i■.>'.^7<■S•J*^:^.*^^:;l 


78 


THE  FUNDUS  OCUU  OF  BIRDS 


^\^  l-^e.     l(I,«.k-...lli«l  Plover  (S.natarola  ...uatarola)  XO. 


Fi^.  H7.     Great  l)„,tard  {Oli,  tarda)  xSJi 


.Macrosropi.  ApfM-aranc^s  of  the  Fundu.,  Oculi  i 


in  the  Preserved  Eyes  of  Birds. 


■.'*'■  ■V'?-<i''  ■'■  V-V 


THE    Fl  XDl-S   APPEARANTES   IN   VAHIOrs  ORDERS  OF  BIROS 


The  prrlrn,  of  tl„.  „sii,il  rliwoli.tc-l.rown 
rolor.  IS  .livi.le.l  into  (i,l)out)  fo.irtron  .on- 
voliit.oMs.  which  .-.re  inon-  masMvc  Im-Ionv. 
They  .•Mend  well  forward  towards  tho  lens. 

At  Ih.-  apparent  junelion  of  th-  jM-clen  with 
the  optic  nerve  the  disc  is  rather  orance-red 
in  tone. 

(;nF;AT  HL.\(K-nA(  KKD  r.iLL.  L(m,.i  mari- 
nii.-.  Ph.le  X\-f.  pa«,-  13.5,  depicts  the  fundus 
a[.IK-arar>.es  of  th,-  left  eye  in  this  species, 
riie  Kcncral  coloration  of  the  evcRround 
vanes  from  a  (hill  ^ray  to  a  (hill  hrown  ~ 
mostly  the  latter  —  traversing  which  are 
many  rechhsh.  choroidal  bloodvessels  niiininjj 
iMore  or  less  in  a  vertical  direction.  It  is  the 
niiinl.er  and  visibility  „f  these  .apillaries  that 
Uivc  the  n-d  tone  to  an  eyegroiind  essentiallv 
iir.xy. 

The  optic  di.ir  is  a  long,  narrow  oval,  f|iii(e 
white,  with  a  <|uantity  of  fine  ^ray  lines  radi- 
ating; III  all  (hrections  from  the  i),ipillary  niar- 
f-'iii.  On  tli<-  inner  asix-ct  of  the  eve^round 
tlie  macula  is  s«-n.  It  is  .situated  ahout  one 
disc-lciiKth  from  the  upper  end  of  the  pecten 
and  half  a  dise-leiiKth  al)ove  the  end  of  the 
same  or>;aii  on  the  inner  side. 

The  iiiiiriila  reseniMes  a  hlue-grwn  flake  of 
irid<-seent  glass.  It  is  of  oval  shai)e  with  a 
reddish-hrown  center,  which,  however,  is 
unprovided  with  a  reflex  ring. 

The  prHrn  apjuars  to  he  in  folds;  the  lower, 
or  l.roader,  portion  e.\teniis  well  forward' 
lowarils  the  lens  and  turns  towards  the  nasal 
side  of  the  l)ir(i's  head.  The  inner  (|uadrants 
of  the  fundus  are  more  easily  seen  with  the 
ophthalmoscope  tlian  the  outer  half  but,  so 
far  as  the  latter  area  is  visil)le,  there  is  no  sign 
of  a  second  macula  on  the  outer  part  of  the 
eyeground. 

Charadriiformes 

Hl.4(  K-MKi.i.iKo  Plover.  SquaUtrola  squa- 
tarola.  (Figs,  hm  an.l  89;  maeroseopie 
view.)  Preserved  eyes  of  this  s|)ecies  present 
a  moderately  broad,  grayish  rilinal  band, 
whose  borders,  drawn  as  pigmented  Ihrough- 
oul.  extend  somewhat  obliquely  across  the 
fundus  from  one  margin  to  the  other.  Near 
the  middh!  point  of  (his  n-tinal  area  is  a  cir- 
eular,  craleriform  <li.sc  so  set  in  the  ribbon- 
hke  figure  that  its  cireumferencv  is  not  pig- 


7!) 

mented  within  the  band  prop<>r  but   is  con- 
tinuous with  the  tinte,!  bonlers  them.selves 
In   some    indivi.luals    there   are    traces   of   a 
groove  111  the  retinal  l)aiid. 

The  p.rten  in  shape  resembles  that  of  the 
Iludsonian  Curlew.  It  has  ^l  sausnge-like 
convohitions;  its  fringed  keel  being  prolonged 
at  the  inferior  extremity  into  a  spinous  ,)rocess 
that  (not  shown  in  the  cuts)  follows  the  eon- 
•avify  of  the  eyeball  and  almost  reaches  the 
margin  of  the  lens.  One-third  of  the  coils 
present  a  concave  surface  to  the  posterior  free 
margin. 

The  infiilapapillary  angle  is  about  .50°. 
In  prepared  specimens  lh<-  eyeball  is  ovoid 
with    axes   8:9.     In    .some   individuals,    also 
there  are  traces  of  a  groove  in  tlu-  n'tinal  band! 
IIiDsoNux  Clrlew.     \„menii,>,  hudmni- 
cus.     (Figs.  H5  and  88;  macroscopic  view  ) 
The  background  of  this   biril's  eve  shows  a 
hroad,  grayisli  hand,  with  evenlv  dotted  bor- 
ders, tliat  extends  almost  horizontallv  across 
three-fourths    of    the    visible    fundus'.     It    is 
equally  divided  throughout  its  whoh'  length 
into  two  parts  by  a  plainly  marked  line. 

The  major  axis  of  the  papilla  i)roj.-ctcd 
towards  the  band  (h'seribcs  with  the  latter  an 
angle  of  50".  It  bi.sects  it  half  the  axial  l.-n-th 
from  the  erater-lik<;  fovea. 

The  pectin,  carrot-s]iap<-d  from  above,  has 
a  fringed  cap  covering  its  upper  free  border 
It  exhil)its  3i  convolutions,  the  spaces  be- 
tween the  middle  ten  being  deep  enough  lo 
allow  a  glimpse  of  the  oi)lic  margins,  that 
are  elsewhere  completely  covered.  The 
i>hi(  k,  free  margin  corresponds  in  shape  to  the 
pi-etinate  body,  being  quite  liroad  below, 
narrow  and  pointed  above.  Its  inferior  third 
IS  prolonged  (into  the  vitreous)  in  the  shape  of 
two  conical  elevations  and  a  long,  single 
notched  spine.  The  crest  graduallv  slop.'s 
from  behind  forward  so  that  tl,e  posterior- 
eoils  air  the  longest.  Two-thirds  of  the  coils 
"face"'  forward. 

Ghkateh  YELLow-i.K(i.s.  Tolann.^  nulnno- 
leucus.  (Figs.  114  and  87;  macroscopic 
view.)  In  this  species  ;i  broad  rctinul  liuiid. 
faintly  depicted  with  pigment  lines,  cMends 
across  Ih.-  entire  visible  fiehl,  its  nasal  half 
being  divided   by  a  double-dotted   line  that 


80 


THE   FUNDUS  OCULI  OF  BIRD? 


•■n.ls  lit   tlic  pi^'iuontcd  rircimiferonfe  of  tho 
ciniiliir  nuifiiln. 

Til.'  mnriihr  rajion,  twice  us  wi.lo  as  llii- 
siim.iiiKlinj.'  I.an.l,  prt-sonts  a  larj;.-,  trnlral 
fovea. 

The  prrlen  has  much  tho  same  shajw  as  in 
Squatiirola;  it  is,  however,  a  little  larger,  aiuj 
has  :!■»  eciivohilions.  The  niediimi  size.] 
coils,  loiijjer  Uallerj  as  one  ai)|)roaehes  tho 
post.TJor  free  margin,  ar<-  cai)i)e(i  hy  a  deep, 
irn'KnIar.  [.arlially  serrated.  iidg<'-iike  crest 
that  lernnii.iles  posteriorly  in  a  sh^rp  point; 
anteriorly  the  erest  heeomcs  much  narrower, 
anil  ends  in  a  tapering  Irian^'ie. 

The  optic  nilnnirr  is  (at  its  middle)  seen 
through  th<-  inlerrnpted  coils  of  the  peeten; 
and  tiie  infuhipapillary  angle,  niach-  l.y  its 
projecte.1  major  axis  and  the  lower  margin  of 
the  retinal  hand  is  hetween  4.")"  and  .^O". 
The  shape  of  this  eyehall  is  oval,  10x11. 
Stoxi;  ri.()\|.:i(.  (Edicnmux  sculopux. 
Tlio  fundus  appearances  (left  eye,  erect  im- 
age)  of  this  nocturnal  hird  are  depicted  in 
Plate  XVII,  ,,age  1:J7. 

The  cyeground  is  a  warm  brown  or  choco- 
late color,  rather  (hrply  pigmented  near  the 
periphery  and  cov<'red  with  orange-red  dots 
that  are  very  densely  packed  on  tho  ui)per 
half  of  the  fundus.  Uelow  the  optic  entrance 
are  numerous  choroidal  vessels  running  paral- 
lel with  and  on  either  side  of  the  papilla. 

The  iiKuiiht  is  diir.iilt  to  distinguish  and  is 
not  clearly  defin..i  vmI,  lue  ophthalmoscope. 
It  IS  situated  ahove  the  sui)erior  end  of  tlio 
disc  on  its  inner  or  nasnl  side,  and  about  half 
the  apparent  length  of  the  peeten  from  the 
upper  end. 

The  fundus  coloring  is  slightly  d.irkcr  in 
the  macular  area,  which  is  surrounded  by  » 
rellex  ring,  [)ale  gray  in  color,  in  the  form'  of 
very  minute  lines  radiating  from  its  margins. 
There  are,  also,  a  few  radiations  near  the 
Jorfn  ctntmli.i. 

The  papilla  is  white,  oval  in  shape,  fringed 
ull  round  with  <lense  black  pigment,  and  a 
few  gray,  opatpie  nerve  fibres  are  seen  on 
either  .side  of  it. 

The  p,T/cii  is  \ery  large  and  projects  well 
into  the  vitreous.  It  is  of  unusual  shai)e, 
rather  narrow,  but  when  examined  from  al>ove 


look.s  ns  if  it  bad  been  compressed  and  flat- 
tened on  both  sides,  with  a  narrow  edge  above. 
Great  Hi  stahii.  Otis  tarda.  (Figs.  H7 
and  90.)  The  macroscopic  reproduction  of 
this  barkgrmind  shows  a  narrow  line  of  pig- 
ment, rei)resenting  the  usual  retinal  baud, 
which  extends  horizontally  across  the  central 
two-thirds  of  the  visible  fundus.  At  almost 
Its  exact  middle  is  an  incompletely  oval  area 
encircle<l  by  a  ring  of  pigment  grains.  A  dark 
spot  (fovea)  more  or  less  surrounded  by 
black  dots,  occupies  the  centre  of  this  crater- 
like  space. 

The  large  and  compact  peeten  forms  a  very 
regular,  oval  figure  who.se  extremities  appear 
to  be  of  practically  the  .sanu-  shajR-  and  size. 
II  is  made  up  of  about  42  convolutions  united 
in  a  crest  that,  from  above,  takes  on  tho  aji- 
pearance  of  a  fisherman's  (cork)  flojiter.  The 
peeten  in  this  .species  is  remarkable  because 
of  the  small  number  and  large  size  of  its  folds, 
because  the  central  five  of  these  are  the  long- 
est, and  because  the  middle  half  of  the  keel, 
or  crest,  is  projected  as  a  tall  cone  into  the 
vitreous. 

Tho  major  axis  of  this  optic  disc  subtends 
an  infulapapillarj-  angle  of  70=  with  the  linear 
retinal  band. 

Gruifonnes 
Kagi-.  Rhinochetus  jubatits.  In  many  re- 
spects the  eyeground  of  this  bird,  as  seen  by 
the  ophthalmoscoiMj.  presents  apjx-arances 
(see  I'late  XVIII,  page  137)  similar  to  the 
fundus  pictures  (Plate  XVII,  page  137)  of  the 
Australian  Stone  Tlover,  except  that  the 
former  has  a  gray  area  above  the  disc,  instead 
of  ,1  n-d  and  brown  one.  The  drawing  is  of 
the  right  e.\e,  as  seen  b.y  the  erect  image. 

Tho  background  is,  in  general,  covered  with 
a  mass  of  minute  dots  that  are  grav  in  the 
upiKT  half  of  the  fundus  and  orange  below. 
The  lower  sectors  of  the  fundus  are  stippled 
with  pigment.  Choroidal  ve.s.sels  are  numer- 
ous and  run  in  rather  straight,  vertical  linos 
on  both  sides  of  the  optic  disc.  They  are 
tlull-orange  in  color. 

The  foiea  is  shown  towards  tho  anterior  or 
nasal  half  of  the  retina,  and  ap|M-ars  as  a 
round  hole  or  crater-like  depression,  brown  in 
color,  which  rcHects  a  grayish  sheen  from  its 


^'    ^^^JTF^^^JT 


11  rs 


,i7.iV,f*j.:^.>'; 


THE  FUNDUS  APPEARANCES 

center.     A  narrow  gray  cirilo  or  reflex  ring 
surrounds  this  pit. 

The  optic  di-ic  hus  its  central  portion  iippar- 
ently  stippled  with  bright  ornnge-red  dots, 
while  its  margin  is  fringed  with  course,  white 
fibres,  that  are  also  studded  will,  hrown  pig- 
ment dots  esjK'cially  near  the  outer  border. 
The  peclen  is  of  the  usual  deep,  chocolate- 
brown  color,  rather  narrow  where  it  joins  the 
disc  but  becoming  much  thicker  and  more 
massive  as  it  projects  into  the  vitreous  towards 
the  lens. 

BiiAZiLfAX    Seriem.\.      Cariama     crhlala. 
This    species    presents    an    ophllialmoscopic 
picture  of  the  right  eye,  erect  image,  that  is 
reprfxluced   as    Plate   XIX,   page   139.     The 
dominant  color  of  the  fundus  oculi  is  a  dull- 
dral).     Over    the    lower    quadrants    of    the 
eyeground  run  rather  straight,  dull-red,  cho- 
roidal   capillaries    that    fade    away    as    they 
n-ach  the  upfM>r  half  of  the  field.     This  region 
is  also  shot  with  a  greenish-blue  muslin-like 
film,   which   is  probably  a  reflection  by  the 
retina  of  light  rays  from  the  ojihthalnioscopic 
mirror.     Above  the  end  of  the  disc  is  a  small, 
round  depression,  quite  clear  of  any  reflex. 
To  the  inner  or  beak  side  of  the  eye  is  the 
circular   macula,    whose   diameter   is   about 
three  limes  that  of  the  cavity  at  the  end  of  the 
disc.     The  center  of  the  larger  circle  is  quite 
clear,  with  the  exception  of  a  bright  shinmier, 
such  as  is  sometimes  seen  about  the  human 
fovea.     The  circumference  of  this  circle  is 
very  sharply  defined,  and  has  a  bright  ring 
around  it  of  glistening  white. 

The  nptic  disc  appears  as  a  long,  white 
oval,  with  irregular  margins. 

The  black-brown,  corrugateil  fxrlen  is  very 
large  and  long;  it  extends  into  the  vitreous 
and  almost  touches  the  lens  with  its  cluli- 
shaped  terminal.  Very  fine  opaque  nerve 
fibres  radiate  at  regular  intervals  from  the 
whole  papillary  circumference. 

In  two  ey<'s  of  this  bird  examined  l)y  the 
writer  there  were,  in  addition  to  the  appear- 
ances just  detailed,  several  .scattered,  red- 
dish-brown dejiosits,  very  slightly  pigmented, 
111  the  choroid.  These  were  found  in  an 
individual  captive  in  the  Uronx  Park  for  four 
or  five  years,  and  were  probably  pathological. 


IN   VARIOUS  ORDERS  OF   BIRDS  81 

Ardeifonnes 
Amehican  Bi,a(  k-chow.ved  Nioiit  Heron. 
Syvticorax     ni/rliconix     nvtiiin.       (Figs.    9< 
and   \i9;  macroscopic  view.) 

There  were  no  definite,  naked-eve  indica- 
tions of  a  fovea  in  the  individuals  'examined. 
The  pertni,  more  pointed  at  its  surM-rior 
extremity,  exhibits  20  convolutions,  .so  .sepa- 
rated that  a  view  of  the  disc  borders  is  here 
and  there  obtained.  The  |H-ctinate  coils  are 
united  by  a  narrow,  cord-like  crest  that  ex- 
tends on  the  same  plane  and  in  a  straight  line 
(except  that  at  its  middle  point  it  is  slightly 
high.T)  along  the  upiier  free  border  from  one 
extremity  to  the  other.  The  coils  do  not 
differ  much  in  length. 

EiHOPEAN-  \ui,iT  IIehon.  \ycHcorax 
nychcorax.  Seen  with  the  ophthalmoscope 
the  rycgroHud  (.see  Plate  XX,  page  13!)j  is 
dull  gray,  covered  with  grayish-while  dots. 
The  lower  part  of  the  fundus  exhil)its  a  num- 
ber of  faint,  reddish  choroidal  bloodvessels, 
that  run  in  a  vertical  direction,  and  who.se 
disposition  is  .similar  to  the  capillaries  .seen 
in  the  fundus  of  the  Boatbill,  depicted  in 
Plate  XXII,  page  141. 

The  optic  dine  is  long,  but  of  medium  width, 
with  both  extremities  roundel.  Its  eenter 
is  orange-red  and  covered  with  minute,  brown 
pigment  dots. 

The  pccten  is  deep  brown  and  its  outlines 
are  well  defined  the  whole  length  of  the 
papilla.  Very  thin  grayish  radiations  extend 
from  the  upper  two-thirds  of  the  oj)lic 
entrance. 

The  macula  is  situated  quite  clo.sc  to  (and 
towards  the  upper  nasal  asix'ct  of)  tlie  di.sc. 
It  is  surrounded  l)y  an  outer  ring  of  whitish 
lines:  then,  towards  its  eentre  is  a  zone  re- 
sembling the  surrounding,  puiiclated  retina. 
In  its  exact  centre  is  a  small  fovea  composed 
of  gray-white  strife. 

(Jkeat  White  Heron.  Anica  occidnitulin. 
The  individual  examined  by  the  writer  had 
been  in  captivity  at  tlu'  Bronx  Park  for  .sev- 
eral years  and  was  slightly  myopic.  The  eye- 
groun<ls  of  both  eyes  appeared  i.lentieai  and 
the  ocular  organs  were  normal.  The  pupil 
contracts  under  the  strong  light  „f  tli<'  oph- 
thalnio.scopie  mirror  to  medium  size. 


Si 


THE   FUNDUS  OCULI  OF  BIRDS 


^-i«.   H9.     Blaok-crowned  Xi.l.t  Iloron  (X.cticora.  nyrHroras  n^u.)  xfi 
Macro«x,pic  Appearances  of  the  FuBdus  Oculi  in  the  Pr«erved  Kye.  of  Bird,. 


7/  T.V'-^-'  -  ■* 


THE   FrXDUS  API'KAHANCES  IN    VAHIOIS  OHDEHS  OF  BIHDS 


I 


Til.-  .Ic.iiiiniint  rolnr  of  the  hm-kgrnu,nl  is 
liKhl-nd.lisli  or  l.r(iwnisl|.«ray  ami  has  appar- 
I'lilly  a  Kramilar  surface. 

Tlif  impilh  is  white,  aliiH.sl  .•iilircly  <ov- 
.•r<'<l  hy  tin-  iM'ctoii  and  seems  shorter  than  in 
most  l>ir(ls. 

The  piclrn  is  imiisiinlly  hirge;  only  its  fri-<. 
en.J,  whieh  is  lilunt  and  rounch-.l,  (an  he  oiit- 
line.l  with  the  mirror.  There  is  no  «el|. 
tiefineil  macular  region. 

Amkiik  ».v  Va.uf.T.  llrrodian  r</r,l.'.,.  \ 
young  adult  was  examined  |,v  ||„.  „ritcr 
in  the  Bronx  Park.  The  dominant  color  of 
the  fundus  in  this  species  is  n  clear,  hright, 
.steel-gray. 

The  pirtni,  an  ohiong  with  rounded  ends, 
<'<.ver.s  most  of  the  optic  disc,  whose  white 
Imrder  can  he  seen  only  on  the  outer  si.le. 
Stnie.  composed  t.f  whitish  opaque  nerve 
fibres,  radiate  from  the  circumference  at 
regular  distances  from  each  other. 

Amkkicav    Uittkhn.     liotaum.t    Imtigimi- 
"ii.".     (Figs.  1-28  and  91. j     This  fundus  when 
seen  hy  the  naked  eye  and  in  prepared  speci- 
mens, .show.s  two  macular  regionn  with  thiir 
fomr.     Till'  forea  uasulin  ~   a.  large  dot  .sur- 
nuinded  hy  a  nebular  ring  —  just  above  and 
slight  I.,    to    the    nfi.sal    side   of   the    superior 
extrennty  of  the  ix>cU!i.     Temple-wards  and 
almost  at  the  periphery  of  the  visible  back- 
ground i.s  the  forea  temporalix  —  a  less  dis- 
tinct area,  also  depicted  as  a  central  spot  sur- 
rounded by  «  ring  of  pigment  grains.     Allow- 
ing for  the  concavity  of  the  eyeball  the  two 
macuhe  seem   separated    (in   the   figure)    by 
about  two-thirds  the  length  of  the  optic  disc. 
The   coralliforni,   fenestrated   structure   of 
the  pectcn  is  nmde  up  of  28  narrow  convolu- 
tions that  are  .separated  at  their  upper  free 
niargins  .so  as  to  allow,  here  and  there,  a  good 
view   of   the   pigment-dotted   surface   cf   th - 
opticus.    There  are  three  (,une(|ually)  .short  ai..- 
eleven      ■  qually)    long    double    (oils    joined 
above  by  a  narrow  but  uniform  crest. 

EiKOPK.w  Bittern.  Botuuru.i  stellaris. 
The  left  fundus  oculi  of  this  species  is  depicted 
in  Plate  XXI,  page  141  of  this  work. 

Tht  eyeground,  tuostly  mouse-coloreej 
shaaing  to  yellow,  is  .sprinkle<l  with  small, 
dull-white  dots. 


83 

Almost  immediately  above  the  upjHr  end 
of  the  oplic  nerve  entrance  and  towards  the 
nasal  side  of  the  disc  is  the  macular  ana.  The 
fundal  dots  at  this  point  are  much  .luller  in 
lone  and  incline  towards  a  dull,  bulf  coh.r. 
The  region  of  the  macula,  enclosed  by  two 
cirehs,  one  within  the  other,  is  nlso'char- 
acterizcd  by  the  presence  of  very  short, 
bright,  bluish-green  lines  radiating  from  the 
center  of  the  fovea.  These  striiilious  are  very 
brilliant  an<l  are  easily  .se<>n  by  the  aid  of  the 
ophthalmos<'o;H-. 

The  nptic  dine  is  ovoi<l,  blunt  at  its  upper 
extremity,  ami  appears  as  if  its  longer  nmr- 
gnis  descril)e  a  .series  of  small  curves  corre- 
sponding to  the  folds  of    the    p<>cten.     The 
disc  on  either  side  of  the  root  of  the  peclen 
is  dull-brown;  near  by  are  small,  orange-red 
choroidal  capillaries.     The  papillary  nuirgins 
are   quile   white   and,    in   contrast    with    the 
shadow  cast  upon  the  neighboring  field  by  the 
dark  i)ecten,  the  disc  stands  out  in  .sharp  con- 
tour.     Kxleudiiig  a  short  distance  over  the 
fundi   and   about   the   oplic   disc   are   a    few 
opa(|Ue    nerve     fibres.       The     i)ecten.     con- 
voluted,  with  .serrated   margins,  and  of  the 
usual   chocolate-brown   color,  extends   below 
the  lower  end  of  the  optic  disc,  and  is  plainly 
visible.     It    does    not    project    far    into    the 
cavity  of  the  vitreous. 

Mo.vT-uiLLKD  Night  Heuon.  Cancroma 
i-.  c:}/-tiria.  The  eyeground  of  this  Central 
.Vmerican  species  is  represented  by  Plate  XXII, 
page  141,  and  depicts  the  left  eye  1...  '.  . ,,  ,t' 
image.  The  prevailing  coloMif.'f,  of  *ii.- 'va-k- 
ground  is  dull-red,  covered  vvi'ii  ocs-in -re  { 
dots.  These  punctate  deposits  are  ir>!.  r- 
mixed  on  the  upi)er  half  of  the  fundus  wi;f, 
smaller  ami  brighter  dots  of  a  gr.u .  ■  lone. 
On  the  lower  half  and  on  each  .side  oi'tl.  ■  ;  l.t 
nerve  are  a  few  orange-red  choroidal  .  jipil- 
lary  vessels,  that  run  in  a  vertical  dirclion, 
parallel  to  the  long  a.xis  of  the  disc. 

The  macula  is  situated  towards  the  nasa. 
side  of  the  nerve  head.  This  sensitive  area  is 
rather  brighter  in  color  than  the  surrounding 
field,  and  several  white  dots  arc  included  in  it. 
These  small  dots,  however,  are  noticeable 
only  when  the  light  of  the  mirror  is  reflected 
on   the  region  in  certain  directions.     Kather 


)m^msMmkf:mm 


84 


«  ImKhl  irrfRularan,!  linear  n-H.-.x  surround. 
t^^K•  nmeulnr  r-Kmn.  whUh  i»  v.-ry  «.„sitiv,.  ,„ 

Tlu-ro  i,  «  \oug,  narrow  p„p>ll„  with  roun.l,.,| 
.•xtrom.tu..  It  „p,H.„r,  „,  .f  j^  „.^.^,.  ,,„,,, 
l«.so.l  of  short,  whit.,  (il.rc-s.  ,urroun.hnK  an 
'>ranK.-.r.-.|  n-ntor  .ovr..,!  with  n.inut...  .lark- 
l.rown  ,„«„,..„,  ,,r,i,„  (^at  f„r,„  „  ...twork 
<•^^^  the-   w^hol..  rt-,1   ar,.a.     Kxtcn.linR  from 

onchs.,,  of  th,.  disc  across  the  n-linaar..  a 
few  dull-Kruy,  opaque  nerve  fibres. 

The  ;v-r/.„  can  l.e  tram!  the  whole  lenRth 
"f  the  disc;  ,t  i.,  ,|„rk  l.rown  in  color  and 
groove.!  spirally  like  a  corkscrew.  It  d.H-s 
""I  <.piHN.r  lo  come  far  forwar.l  towards  the 
l'-"Y  "-l  "s  union  with  the  nervehead  can 
readily  Ik.  traeed.  The  peCen  and  its  im- 
.ned|ate  relations  remind  one  of  the  fundus 
oculi  of  the  Bitterns. 

r.u.HHV  I„,H.  rirgaJi,  falcinellu.,.  U 
will  he  seen  on  examiniuK  Plate  XXIII.  paue 
1  tJ.  representiuK  th.-  left  fundus  o,uli  of  this 
HjK-<'i,-,s,  the  general  coloration  is  l.hie-Krav 
the  .-ye^round  Ik-Iuk  covered  with  a  nel.ula  of 
nnnu te.  pale-^ray  dots.  Riving  i,  „  ,.H|ii,.„( 
Kra.N  tone  when  lighted  up  l.y  the  ravs  from 
tne  o()litlialnioscoi)ic  mirror. 

Towanls  the  lower  part  of  the  fundus  and 
o.  bo  h  sides  of  the  optic  disc,  hut  parallel 
With  It,  are  many  oranKe-red  <horoidal  capil- 
aries;  they  are  especially  numerous  l,elow 
he  optic  nerve  and  suffuse  the  ,>,.ri,,heral 
l.ack^roun.1  with  an  oran^e-pink  glow 

tJny    one    sensitive    area    is    swn.     This 

m«c«/«r  .,,,.„  is  loeated  above  the  disc  on  the 
nasal  side  of  the  nerve.  In  the  cente- of  H,,. 
area  is  a  small,  while,  round  dot.  sum..m,l,  ,1 
by  a  brilliant  blue-Krt.M,  reflex,  like  the  sImtu 

on  floss  silk.  It  is  probably  due  to  the  plav 
of  l.Kht  on  the  fine  fibres  radiating-  from  the 
center  of  the  fovea. 

The„p^V.rf,>  looks  as  if  i(  ,.,.,.,  „  „,„,^ 
"f  coarse  white  fibres;  it  is  sm.iiar  in  slia,K. 
«>  the  papilla  of  the  .Spoonbill,  but  it  can 
'e  traccl  only  for  about  half  its  le.,«th 
the  lower  part  beiuK  obscured  by  'he  mas- 
sive club-sha,,ed  peclen.  The  di.'-  is  bor- 
dered with  black  pigment  whi.h  gives  the 
appearance  of  a  sha.low  cast  on  the  eve- 
ground.     This  organ  is  of  the  usual  chocolate- 


TIIE   FrXDl'S  OtlXl  (»F  BIHDs 


brown  color  and  project,,  well  forwar.!  towards 
tne  lens. 

A  large  number  of  semi-transluceni  nerve 
hlM-rs  ra.jiatc  fr.mi  the  margin,  ,.f  Ihe  opliV 
nerve  on  „1|  .si.les;  they  exten.l  a.ross  the 
ehoroidal  vessels,  ami  finally  vanish  alto- 
gellier  in  the  fiindal  |)eriphery. 

AUKHI.  AN    Jabiku.      Mycl,ria    amerirana. 
The  fundus  of  the  lef,   eye  is  .lepi..ted   in 
I  ate\\I\.p,^„.  ,4;,  by  the  direct  method. 
Iho   !„nrral   coloration    is    «    slate-grav.    the 
whole     eyegroun.l     U-ing     ,,uit,-     uniformlv 
sprinklci    with    small    but    varinuslv    si/,.,i 
»Wutedots.     In  the  upper  and  nasal  ."luadranl 
of  the  pict.m-  is  the  small,  single  macula,  an 
an-a  darker  than  the  surrounding  parts,  whose 
exact  centre  shows  a  round  white  dot     -  the 
Mca.     In   the  lower  two-thirds  of  the  (iri.l 
are  seen  numerous,  plainly  niarkcl  ,|,„roi.|,d 
vess,.|s  (hat  extend  the  whole  length  .,f  the 
pecten.    conv.-rging    .somewhat    towards    th.- 
p.>sterior    a^jM-ct    of    its    base.     About    l»o. 
thirds  of  th,-  long  an.l  rather  broad  ncrn-l„a,l 
is  plainly  visible,  e.xc«.pt  the  central  portion, 
which  IS  pa.  tly  obscur..<l  I  y  the  pcrfn,.     This 
arge,    black-brown    organ,    divided    into    I.-, 
arg.-  and  .s,.veral  much  smaller  double  folds 
termmates  above  as  a  thin,  dark  rod      The 
dis,.  IS  fringed  by  black  pigment  grains,  an.l 
from  Its  hiteral  margins  proj,.ct  a  mimlHr  of 
short,  faint,   whitish   lin.-s. 

Si'.).)VBrLL.  Plalolca  leucor.nlia.  T|,..  ,.„| 
or.-.l  fundus  view  (see  Plate  XX \',  pag,.  I »-,) 
is  of  th,-  eret-t  image,  left  .-ye.  In  «.,,era| 
lie  .-olor  of  the  cy,gro,md  is  .l.-ei.l.-.llv  graN- 
"•'•o"'inK  brownish  f.,war.|s  th.-  ,H.i'ip|„.rv.' 
It  will  be  noted  that  the  entire  fun.lus  is 
t  '"ekly  sprinkh-d  with  minul...  imguiarlv 
sh...,H-,l  gray-whit.,  dots,  th;.t  app,.ar  mon- 
distinct    about   the  macular   ivgion. 

At    the   fovea,    where    th..y    an-    briiliaiil 

wh,  e,    tlK.y   «„•    still    more   .losely    p,....k,.,J. 

Uith   the  .>phtlialmoscop,.  th,-  fov,.al   r.gion 

apiH-ars   to   be   sunk.-n    bel,.w    its   surrouml- 

iiips,  andtobe.-ne!.,s,.din..  pal..,  g,,..,.i,h 

reflex)   ring  that  ,,  of  oval  slia,K.  with   its 

long    axis    horizontal.      Ju.lging    from    the 

e  r..ct  on  the  bird  when  the  direct  light  from 

tlie  mirror  is   thrown   upon  it,   this  ari-a  is 

extremely  sensitive  to  light. 


.^BSiSIS^s?^ 


3 

I 


TIIK   FINDCS  APPKAHA.VCES  IN   VAHIOIS  OHDIIHS  OF  HIHI» 


Tlir  <>|iii<'  ri.-rvi -.iilrntKr  i,  n  U,un.  imrniw 
oval,  iiihI  |irf,.iilN  «  l,rilli,,til  ulijlr  ,i|.|Hnr- 
iiiKf.  Wjir  its  u|.|KT  <-ri<l  iirv  srv.nil  choroi- 
•lal  <ii|.ill,iri.-s  of  II  iml,..  j;,,|,|,.„.y,.||„„.  ,.„|„r. 
I'anill.l  I.,  til.-  liiiiK  axis  of  th.-  li.rvr-lnii.|  in 
iiiiotlicr  flHiiKali-.l  iiiasN  of  uliji,  (il.r,.,  • 
(iilMio,t   likf  a  vcoiid  o|ili,'  ,1,.,  ,   liiiviiiK  its 

r.'iil.T  Mi|.|)!r.|    will,    tin,,   pii; „t    .lot,,   ali.l 

.•M.'iMJinK  a.n.xs  ||„  ,y,.Kro,iiHl.  Ha.lialii,^ 
from  lh<-  .inimif.Ti'iH,-  of  ||„'  papilla  on,- 
x'fs  a  miijiiIkt  of  faint.  Inin.lii,,.|it  fil.rcs, 
(TosMiiK  lhc>  small  whit,.  ariM  on  tlir  iia.al' 
side   of   tli<>    n«T\f, 

The  /).(7</(  cl(«-,  n,i|  proji.cl  very  far 
forwar.l  into  tlit-  vilrroiis;  it  is  dark  «rav- 
l-rown  and  app,.ar>  to  I,,-  compN-tcly  fovt-ml 
with  a  iiiindM.r  of  waiiy  proliilMTanc.'s. 
Il  app,ars  to  l„.  atlaolinl  to  tli<'  who!,-  l.nKlIi 
<»r  III,-  .-..ntrr  of  ||„.  diM',  that  is  siippl,.,! 
with  fine,  ri-d  <|ots. 

Anserifonnes 
Hl.A,K-HKM.iKi)  TliFi:  DtrK.  Dnulro- 
<!/!i,ia  <iiit>imii„tl.t.  Till-  fundus  appearances, 
as  r(-v(-ali-d  liy  the  oph||ialniosi-,)p<-  in  six 
i-yi.-  of  three  indivi,liiaN,  are  d,-pi,|,-,i  as 
I'iale  \X\I,  pa>.'e  H.j.  Five  normal  eye- 
«roiin,N  wen-  i,lenli<;il;  ||ie  sivlh  exhiliiled  a 
e,)liKenilal  .h-leel  of  the  nerve-h<ad  whieli 
t-iilirely   ehan«ed    the    fundal    pi<tiire. 

Tlie/»»(/)(.v  ,)(.;//(■  of  111,.  Tree  Duck  is  colored 
a  litflit  fawn,  besprinkh-d  with  minute,  white 
•lots,  that  Klislen  wh,-ii  a  strong  lijfht  from 
the  mirror  is  thrown  upon  them.  On  ,.a,li 
side  of  th,-  papilla  is  s(-<-n  a  iiunil(er  of  ihoini- 
-lal  .aiiillaries.  Iirinht  orange  in  color  and 
rather   strai^rhl. 

The  i>i)lic  ,//.«,.  is  also  orange-red  aloiij;  its 
major  axis,  lliis  o-ntral  zone  In  in^  stippled 
all  over  wilh  a  n<-twork  of  fin,-  j.lack  .hds. 
Tin-  circumft.rence  of  the  <lisc  is  friiifjt-d  with 
while  lilires. 

The  dark-hrown  ixclcii  arisi-s,  as  usual, 
from  111,-  whol,.  leiiKlh  of  ||i,.  disc.  Viewe,l 
from  aliov,-  it  .seems  very  thin  and  twiste.i, 

•  \\  IhIIkt  llii>  \h  u  iiDriiial  conditiori  or  un  anomaly 
of  dcvilopm.nt  raiini.t  Ih.-  d.-finiielv  staid  without 
un  ,\.iiiiiMalion  of  additional  s|K-«iimns,  but  il  was 
Iir<-.-..iil  in  both  cyt-s  of  the  individual  undur  uon- 
sideratiuu. 


M 

like  a  corks,r.-w.  A  few  <ipa.|uc  n.-rve 
fil.res  exieii.l  for  a  ,|iort  ,li>lanc..  and  at 
riK'lil  aii(,'l,-s  to  ||„.  ,|i„.  „„  ,.i||„.r  ,j,|,,  .,.||^. 
il|)|H-r  part  of  III.-  fiiinjiis  is  almost  ol„eiir,-,l 
l.y  iiiimi-roii,  niiniil,-,  l.rillianl,  whil,-  dot, 
Allhouk'h  ll.-a.l  noli,.,-,!  Ihal  wli.,,  he  f,M-Us.-.| 
the  l.riKJil  liKhi  of  ih,.  mirror  „„  the  upp.i- 
<|uadranls  of  |h,.  fun.lns  ih,.  I)u,.k,  us.-,| 
th.ir  iiK-mhrana  nic-litan-  nior,-  fre,|ii,nlh 
than  Usual  he  lould  not  ,liseovi.r  any  \\r\\- 
detineil  s,.n-iliv,-  ar,-a. 

Hl.l  K-WIN,.KI)  TkaL.  Q>„rqi,al„l„  ,li.i. 
fori.  Th,-  >;,-n<-ral  iipp,-,iriii.<,-  of  this  liinl's 
ey.Kroiind  ,l,.„|y  approaches  thai  ,if  tin- 
Mallard.  Th,-  lol|^.r.  „v,,i,|  pa|,illa  is  di,pos,,l 
with  its  inajoi  axis  at  ri^lil  aiiKh-s  t,,  U,,- 
iipjH.r  niandihli 

Mandaiiin  1)1,  k.  Air  ;;(il,rir,il„l,i.  In 
examinini;  Ih,-  .•y.->;rounil  of  this  >p,.,.i,.,  H,,. 
wril.'r  fouiKJ  |l,.,i  th,.  lij;hl  ,,f  Ih,.  ophlhal- 
inoscopi,.  mirror,  when  project,-,!  on  H,,- 
ey.-s  ,lir,-.ily  from  the  front,  ilhimin.il,.,, 
roiiijhly  >p,-akin>.'.  about  om--si\ili  of  ,.,„.i,' 
field. 

Till-  prevailiiif,'  ,.o|,,r  ,,f  ih,.  ba,  kurouii,! 
is  lijilil,  «ray-browii,  str,-ak<-d  with  faintly 
marked  ,h,iroi,lal  cai>illari,-s,  thai  ar,'-. 
liow,-v.-r,  con(in,-d  to  Ih,-  na-al  si,h-  of  ih," 
ilis,-. 

The  direct  nielho,!  shows  a  v,.rli,..illv 
plai,.(l  ,)/)//,.  rnlniiicr.  that  appears  to  slrehh 
almost  ov,r  Ih,-  whole  fundus.  The  fi.jd  on 
I  lie  out,r  asp,-ct  of  the  dis,-  seems  t,)  be 
siip,-rficially  roiiKliem-d  or  Kranul.ir.  Tlu-re 
lire  no  railialin;;  opa(|ue  n,-rve-hbr.s  or  con- 
ceiiiri,    rellex  rinj;s  visibl,-  wilh  lh<-  miri-or. 

The  iKctcn  is  comparatively  small,  doe,  not 
entirely  covi-r  the  dis,-  and  picsents  fr,iiii 
iibov,-  ilowiiward  a  retir  ulaltd  appeaMiiei-. 
M.\Lr,Ani)  I)i  <  K.  A.iii.s  homi.t.  The 
Ken,-ral  (■(iloniUnii  ,>/  the  fiiiidii.i  of  this  bird  is 
Kray-n-d.  Th,-  „/)//,•  m^rie  vntranrc  is  much 
longer  than  in  most  species,  extending  in  a 
p<-rpeiidiciiiar  fashion  across  the  baekj;round; 
it  is  in  no  place  obscured  or  entirely  hid  by 
the  pectea.  The  papilla  apjiears  to  be 
attached  for  tlir<-o-fourths  of  its  course  to 
the  latter,  which  arises  in  partially  trans- 
lucent, veil-like  folds  and  extends  1..  the 
posterior  surface  of  the  lens.    Xo  concentric 


■^ww 


86 


THE    FUXDUS  OCULI   OF  BIRDS 


<ir(lfs  of  ()|)ii(nic  iicrvi-  fibres  are  vislMe. 
The  whole  haeksround,  inehidiriK  the  dise, 
seeriis  to  hv  dotted  witli  many  piinclate 
|iit;tiieiit  grains. 

Canada  (ioosi:.  Braiila  rdnnihnniK.  The 
iiidivi(hial.s  of  this  s]K'cies  examined  hy  tlie 
writer  liad  lieen  (h)mestieateil  in  the  JJronx 
I'ark  for  .several  years  hut  under  con<iitions 
approaching   their   usual   hal)itat. 

Tile  appearances  of  X\w  fundiis  ociili  were 
l)raetiealiy  identical  in  all  the  specimens 
exannned,  and  are  similar  to  those  of  the 
Mallard.  The  concentric  arrangement  of 
Ihe  o|)tic  fihres  in  Anas  is  lacking  in  the 
Brant,  while  the  latter  has  the  larger  pecfen. 
Although  the  prcfen  is  rather  large,  the 
outlines  of  the  vertically  oval,  yellowish- 
white  papilla   are  visible  throughout. 

Blie  (Snow)  (ioo.sE.  Chen  ccendesccnu. 
Plate  XXVII,  page  147,  reproduces  the  fund- 
us appearances  of  two  individuals  examined  by 
Mr.  Head  and  of  another  seen  by  the  writer. 
The  backgrounds  were  the  same  in  all. 
The  predominant  funded  color  is  ii  distinct 
fawn,  sprinkled  with  small,  round,  orange- 
I)ink  dots  of  irregular  shape  and  size.  Run- 
ning vertically  past  and  parallel  with  the 
optic  papilla,  over  the  lower  half  of  the 
fundus,  are  numerous,  straight,  orange-red, 
choroidal  capillaries. 

The/o(T«  is  probably  indicated  by  a  small, 
glistening  white  dot  above  the  end  of  the  disc 
on  the  nasal  side.  This  small,  punctate 
deposit  nearly  disappears  when  the  light 
from  the  mirror  is  turned  in  certain  directions. 
An  inconstant,  bright-green  reflex  is  .lotice- 
able  in  this  part  of  the  eye,  and  there  is  a 
decided  photophobia  when  the  ophthal- 
moscopic light  is  flashed  upon  the  region 
of  the  supposed  macula.  Moreover,  by 
careful  focusing  the  circumference  of  the 
fovjal  (?)  (lot  shows  a  small  brown  rim,  like 
th.-  sides  of  a  crater.  However,  the  light 
from  the  mirror  does  not  reveal  any  actual 
depression;  the  cyeground  appears  level 
throughout  and  is  uniform  both  in  color  and 
texture. 

iThe  optic  nerve-head  is  boat-shaped,  tinted 
orange  along  its  central  zone  and  shows  a 
narrow  rim   of  coarse   opaque  nerve   fibres 


that  form  a  fringe  about  its  circumference. 
This  orange  centre  is  sprinkled  with  numer- 
ous minute,  dark-brown  or  black  dots.  A 
few  gray  opaque  nerve  fibres  arise  from  the 
disc  margins,  and  cross  tlie  fundus  horizon- 
tally. The  pecten,  of  corkscrew  shape,  runs 
the  whole  length  of  the  disc  and  comes 
well  into  the  vitreous. 

Lessek  S.vovv  Goose.  Chen  hyperborcens. 
(Figs.  93  and  131.)  There  is,  judging  from  a 
naked-eye  survey  of  this  fundus,  a  grayish 
but  well-defined,  rather  narrow,  retinul 
band,  devoid  of  pigment,  that  runs  obliquely 
through  the  center  of  the  field  from  one 
periphery  to  the  other.  It  is  more  definitely 
outlined  by  pigment  grains  on  its  inferior 
than  on  its  upper  margin,  especially  where 
it  traverses  the  nasal  half  of  its  course. 
About  its  middle  point  is  the  single  macular 
region  and  fovea  — &  short  but  regular  line  of 
pigment  in  the  center  of  an  enlargement 
of  the  band. 

The  large,  shoe-shaped  pecten  is  com- 
posed of  24  heavy,  compact  convolutions 
that  terminate  in  a  cigar-shaped  superior 
and  a  triangular  inferior  extremity.  The 
conical  crest  of  the  upper  free  border  is 
wide  for  three-fourths  of  its  entire  length. 
It  terminates  in  a  thin,  corkscrew  process 
before  it  reaches  the  tip  of  the  upper  con- 
volution, which  almost  touches  the  reti-ial 
band,  with  which  the  (projected)  major 
axis  of  the  nerve-head  describes  a  right 
angle.  The  convolutions  decrease  pari  passu 
in  size  from  behind  forward,  all  the  coils 
inclining  towards  the  lower  end  of  the  disc. 

Phoenicopteriformes 

Common  Old-would  Flamingo.  Phoe- 
nicopterus  roseus.  (Figs.  94  and  115;  macro- 
scopic view.)  This  ocular  background  shows 
a  small  but  compact  pentcn,  whose  18 
convolutions  are  (apparently)  drawn  towards 
the  center  of  the  organ  above  by  a  deep, 
cigar-shaped  crest,  so  that  the  niarsupium 
resembles,  when  viewed  laterally,  a  truncated 
cone. 

Stretching  obliquely  across  the  fundus  is  a 
light-colored,  retinal  band  of  medium  width, 
which  ends  abruptly  just  before  it  reaches 


THE   FUNDUS  APPEARANCES  IN   \ARIOUS  ORDERS  OF  BIRDS  87 


'  r 


Fig.  131,  Ia^sscf  Snow  Goose  (Chen  hyperborea)  X9. 
Macroscopic  Appearances  of  the  Fundus  Oculi  in  the  Preserved  Eyes  of  Birds. 


88 


THE  FUNDUS  OCULI  OF  BIRDS 


tiio  temporal  Iwrdcr  of  llio  field.  Two  lines 
of  pigment  dots  —  the  one  at  the  nasal  end 
more  plainly  marked  and  eaeli  as  long  as 
the  disc  — divide  the  terminals  of  the  hand 
into  two  narrow  spaces.  The  lower  margin 
of  the  band  is  drawn  with  nunierons  niinnte 
pigment  grains  that  are  sparsely  supplied 
to  the  upper  liorder  except  at  its  nasal  end. 
A  third  line  of  pigment,  deeper  in  color  than 
the  other  two.  atu!  about  as  long  as  the 
papilla  is  wide,  indicates  the  middle  point 
of  the  hand  somewhat  nearer  its  temporal 
end.  At  this  point  the  hand  becomes  slight- 
ly broader,  especially  below.  In  the  centre 
of  this  shortest  line  the  pigmentation  is 
somewhat  pronounced,  but  an  outline  of  thi 
ordinary  slil-like  forea  within  a  retinal  band 
is  not  here  well  developed. 

An  extension  of  the  long  diameter  of  the 
papilla  to  meet  the  lower  border  of  the  retinal 
band,  makes  with  it  an  infulapapillary  angle 
of  CJ°. 

Pelecanifonnes 

Cormorant.  Phalacrocorax  earho.  The 
fundus  view  shown  in  Plate  XXVIII,  page 
147,  of  this  work,  represents  the  ophthalmo- 
scopic examination  of  eight  eyes  of  four  indi- 
viduals. Two  were  tame  birds,  the  others 
were  freshly  caught,  but  their  eyegrounds  were 
identical.  The  drawing  presents  the  appear- 
ances in  \hi  left  eye  by  the  direct  image. 

The  fundus  oculi  is  mostly  of  a  slate- 
gray  color,  uniforndy  sprinkled  with  numer- 
ous, minute  white  dots,  closely  packed 
together.  Running  chiefly  parallel  with  the 
long  axis  of  t!ie  optic  disc  are  several  rather 
straight,  orange-red  choroidal  capillaries, 
that  extend  the  whole  length  of  the  papilla 
and  beyond  its  inferior  extremity. 

The  macular  area  is  seen  a  little  al)ove  the 
upper  end  of  the  optic  disc  and  on  the  nasal 
side  of  the  nerve.  The  fovea  aiJjH-ars  as  a 
reflex  image  of  a  few  short,  bright,  white  lines 
surrounded  by  a  narrow  and  similar  ring. 

The  optic  dine  gives  the  impression  that 
it  is  composed  of  a  mass  of  very  white, 
cotton-like  fibres,  disposed  iis  a  fringe  all 
about  the  papillary  margin.  The  central 
area  of  the  disc,  especially  on  each  side  of 
the     root    of    the    pecten     is     orange-red, 


stippled  with  minute,  brown  pigment 
grains.  Perpendicular  to  the  papillary  mar- 
gins are  a  few  short,  fine  opaciue  nerve 
fibres,  that  run  towards  and  are  finally  lost 
in  the  peripheral  eyeground. 

The  pecten  is  rather  long  and  of  the  usual 
chocolate-brown  tint;  it  is  much  narrower 
than  usual  on  the  upper  half  of  the  <lise, 
and  comes  well  forward  into  the  vitreous 
humor,  extending  behind  the  margin  of  the 
pupil. 

Fallahonf.  C'orm(.rant.  Phalacrocorax 
dilophu.1  albociliatiiK.  An  adult  individual  of 
this  species  (while  dying)  was  examined 
by  the  writer  in  an  open  boat  in  San  Diego 
Bay,  California.  An  ophthalmoscopic  view 
was  obtained  under  these  difficulties,  and 
is  consequently  incomplete.  However,  the 
writer  saw  through  dilated  pupils  that  the 
fundus  was  gray-black  and  uniformly  dotted 
throughout.  The  pecten  was  easily  seen, 
but  not  well  enough  to  count  or  accurately 
describe  the  arrangement  of  its  plications. 

Brandt  Cormorant.  Phalacrocorax  pc- 
nicillatun.  (Figs.  95  and  130.)  This  fundus 
ocuii,  when  viewed  with  the  naked  eye,  in  pre- 
pared specimens,  shows  a  broad,  gray  baud 
depicted  in  the  black  and  white  drawing  as 
extending  in  a  rather  oblique  direction  from 
the  nasal  periphery  of  the  field  to  a  point  im- 
mediately above  the  supt  ior  end  of  the  pa- 
pilla. Here,  just  before  it  terminates,  the 
band  widens  and  develops  into  an  oval  area 
with  a  large  central,  black  dot,  crowned  by 
minute  and  scattered  pigment  grains.  This 
macular  area  is  located  about  the  width  of  the 
minor  axis  of  the  optic  disc  from  the  upper  ex- 
tremity of  the  latter. 

[In  the  temporal  m"rein  of  the  black-and- 
white  drawing  is  a  si  mark;  this  is  7iot  a 
second  fovea  but  an  ariciact  fold  in  the  retina.] 

The  pecten  presents  a  broad,  and  rather 
long,  pointed  oval,  with  its  blunt  extremity 
below.  It  is  composed  of  32  convolutions 
whose  free  margins  are  united  above  in  a  keel, 
and  whose  wide  and  thicker  posterior  fourth 
covers  nine  equally  long  double  coils.  It 
then  slopes  to  the  superior  pointed  extremity 
of  the  disc,  having  joined,  above,  the  remaining 
nine  unequally  short  coils. 


THE  FIXDIS  APPEARANCES  IN    \   /IIOIS  ORDEHS  OF  BIRDS 


80 


Gannet.  Siilti  hoKsana.  The  picliirc  of 
the  fundus,  as  shown  in  Pliilc  XXIX,  page 
149,  is  llie  result  of  ophthahnoseopie  exami- 
nations of  three  healthy,  adult  specimens.  It 
depicts  the  left  ej'e;  erect  iniase.  The  general 
tjlor  of  the  eyeground  is  dull-yellow  with 
a  gray  tint,  everywhere  covered  with  light 
gray  dots,  that  are  most  numerous  on  the 
up|H>r  half  of  the  fundus.  Below  and  on 
each  side  of  the  optic  nerve  are  several 
orange-red  choroidal  capillaries.  These  ves- 
sels are  fairly  straight  and  run  parallel  with 
the  long  axis  of  the  disc. 

The  nerve-entrance  and  pecten  are  situ- 
ated rather  high  up  in  the  field;  consefiuently 
it  is  easy  to  examine  the  details  of  the  jxri- 
papillary  background. 

Above  the  upper  end  of  ihe  optic  disc 
and  a  little  towards  the  nasal  side,  is  a  small 
circular  macular  area,  red  in  tone  but  sur- 
rounded by  a  larger  circle,  like  a  gray  shadow. 
The  margins  of  the  latter  gradually  fade 
into  the  background. 

The  visible  margins  of  the  papilla,  apparent  ly 
composed  of  coarse,  white,  opaque  fibres, 
are  not,  as  in  many  species,  covered  by  the 
pecten.  The  central  part,  near  the  root  of  the 
pecten,   is  orange-red   in  color. 

The  pecten  itself  is  evidently  attached  to 
the  disc  for  nearly  its  entire  length,  and 
does  not  appear  to  come  forward  towards 
the  lens. 

Redback  Pelican.  Pelecanun  riijencens. 
The  individual  (male)  examined  by  the 
writer  was  five  years  old  and  had  been 
domesticated  in  the  Bronx  Park  for  at  least 
three  years.  His  refraction,  estimate<l  by 
the  skiascope,  was  about  -M.D.  The  general 
coloration  of  the  ocular  background  is  a  well- 
diffused,  light  reddish-brown;  in  some  parts 
of  the  field  verging  on  gray.  The  pecten  is 
very  large  —  larger  at  its  free  than  at  its 
papillary  extremity  —  and  twelve  distinct 
corrugations  in  it  are  visible  and  can  be 
counted  by  the  aid  of  the  ophthalmoscope. 

Although  the  canoe-shaped  optic  papilla 
is  almost  entirely  obscured  by  the  mass  of 
the  pecten  yet  it  is  uncovered  towards  its 
temporal  end,  where  it  presents  a  very 
white,  pointed  extremity;  elsewhere  it   ap- 


i-i'ars  reddish-brown.      Radiating  filtres  sur- 
round the  disc,  like  a  halo. 

AlHTHALlAN  Pelkax.  Pelecuiii.s  aill- 
■tpicillatiin.  The  fimdus  appi>aranevs  of  t!iis 
bird,  as  demonstrated  by  the  oi)hthalm()- 
scofx',  are  portrayed  in  Plate  XXX,  page  '  '••'. 

The  i)redominant  color  of  the  eyeyrouti 
is  a  dull  but  deep  gray,  sprinkled  g(  nerally 
with  irregular  dots,  most  numerous  in  the 
upf)er  part  of  th<>  fundus.  The  lower  fjuad- 
rants  of  the  field  are  covered  with  a  dull, 
orange-red  choroidal  capillary  system,  dis- 
posed in  a  vertical  direction.  The  dine  is 
a  wide,  pointed  oval,  exhibiting  a  numlxT  of 
l)right-red  orange  ridges  that  are  uniformly 
stippled  with  l)lack  pigment  dots.  The 
disc  margins  stand  out  as  a  dear  white. 

The  pee  ,t,  broad  and  massive,  seems  to 
fill  the  pupillary  area.  It  projects  far  into 
the  vitreous,  reaching,  indeed,  the  posterior 
surface  of  the  lens.  In  spite  of  its  large 
size  and  intraocular  disposition  both  the  free 
and  the  attached  ends  of  the  organ  can  be 
outlined  by  the  ophthalmoscope.  Passing  in 
a  radial  direction  from  i^  circumference  is 
a  number  of  opaque  nerve  fibres. 

The  single  macular  area  is  to  be  found  on 
the  inner  side  of  the  fundus.  It  is  surrounded 
by  a  narrow,  sharply  defined,  reflex  ring  of 
greenish  color. 

Califohxia  Browx  Pelicax.  Pelecanu.i 
californicun.  A  young  adult  was  examined 
on  the  Coronado  Islands,  Mexico,  by  the 
writer.  The  pupils  measured  about  5  mm. 
and  were  not  affected  by  light,  as  the  bird 
had  just  died.  The  fundus  was  well  seen. 
There  was  a  distinctly  whitish  hcekground, 
almost  uniformly  covered  with  niiimte  gray- 
black  dots.  The  pecten  was  large,  and  of 
the  corkscrew  tyix?,  almost  covering  the 
whitish-yellow  optic  disc  whose  margins  were 
easily  made  out.  This  bird  seems,  from  the 
position  or  his  ej-es  and  their  frontal  disposi- 
tion, to  have  binocular  vision. 

Serpentariiformes 
Secretahy   Bird.     Gypogeranus    (rel   Ser- 
pentarius)    serpentarius.    The    ocular    back- 
ground of  this  species  presents  a  most  unusual 
appearance.    The    colored    drawing    (Plate 


90 


THE  FUNDUS  OCULI  OF  BIRDS 


XXXI,  page  li51),  ikpicts  the  right  fundus 
l).V  the  »Tocl  iiimgo.  The  gi'iienil  color  of  the 
<!/i(jroiind  is  <hili  gray,  jjitted  all  civer  \ith 
mixed  liglit  and  (hirk  brown  pigment  grains  or 
dots,  the  darker  iH-ing  about  double  the  s=ze  of 
the  hgiiter  granules.  Interspersed  with  these 
dots  is  u  dense  mass  of  minute,  bright  points 
that  cover  the  whole  fundus,  but  they  can  be 
observed  only  when  tlie  reltected  light  of  the 
mirror  is  focused  upon  them.  These  various 
deposits  give  the  l)aekgroun<l  the  apjx'arance 
of  a  rough  surface.  There  are  no  visible 
choroidal  bloodvessels,  but  a  thin  layer  of 
translucent  nerve  fibers  surrounds  the  papilla 
for  a  short  distance,  particularly  along  the 
long  axis  of  the  nerve-head. 

A  little  above  the  upper  ond  of  the  optic 
disc  and  towards  the  nasal  side  is  the  forea 
centralis,  a  round  white  dot  enclosed  by  a 
narrow  ring  of  bright  green.  This  area  is 
extremely  sensitive  to  the  reflected  light  of  the 
mirror.  On  the  temporal  side  of  the  disc, 
and  above  the  end  of  it,  is  also  a  long,  narrow, 
sensitive  area.  This  part  is  enclosed  by  a 
shimmering  reflex  of  green  light.  The  animal, 
otherwise  quiet,  becomes  very  fidgety  when 
this  area  of  the  fundus  is  examined,  and  gasps 
for  bn*ath  as  if  it  was  being  suffocated. 

The  opt)V  disc  is  long  and  rather  narrow, 
both  ends  l)eing  rounded  off.  It  is  quite  white 
and  deeply  pigaiented  at  its  outer  and  upper 
borders. 

The  pecten  is  of  a  lighter  brown  than  usual, 
is  plainly  serrLtea  on  either  side  and  appears 
as  a  narrow  band  that  extends  the  whole  length 
of  the  disc.  .Just  before  its  junction  with  the 
optic  nerve-head  it  is  stippled  with  bright, 
orange-red  grain  The  central  part  of  the  pec- 
ten does  not  project  far  forward  into  the  vitre- 
ous; it  appears  to  be  quite  narrow,  while  the 
whole  length  of  its  upper  edge  or  crest  seems 
rather  wavy.  On  the  whole,  the  fundus  ap- 
pearances present  a  picture  unlike  those  oi  any 
other  species  examined  by  Head  or  the  writer. 

.\ccipitriformes 
Lammergeier.     Bearded  Vulture.     Gypae- 
f;s  barbatus.     Plate  XXXII,  page  151,  repre- 
Sfcut:i  an  ophthalmoscopic  view  of  the  right 
ocular  fundus  (erect  image)  of  this  bird. 


The  eyeground  is  slate  gray,  not  stippled,  as  in 
so  many  avian  fundi,  but  presenting  every- 
where a  granular  appecrance.  The  lower 
half  of  the  fundus  is  cover- d  with  dull,  orange- 
red  choroidal  bloodvessi  1  s  that  run  in  a  ver- 
tical direction,  parallel  to  the  sides  of  the  oi)tic 
disc. 

Above  the  papilla  (about  two  disc  breadths 
from  it  on  the  na.sal  side)  is  a  snuill,  round, 
dark-brown  pigmented  pit,  surrounded  by 
two  distinctly  marked,  brilliant  reflex  rings, 
each  having  a  greenish  tint.  On  the  nasal 
side  of  the  nerve-head,  but  quite  near  the  disc, 
and  much  less  distinctly  outlined  than  the 
depression  just  described,  is  the  second  macnlar 
region  with  its  fova.  Looking  at  it  through 
the  mirror  it  seems  to  have  a  soft,  indistinct 
but  dark  center. 
All  the  fundal  sectors  are  clearly  seen. 
The  optic  entrance  is  pure  while,  with  an 
orange-red  central  area  from  which  arises  the 
pecten.  This  body  is  very  narrow  an<l  lajK-rs 
on  its  upper  aspect  for  about  one-fifth  of  its 
length.  It  then  becomes  much  broader  and 
almost  covers  the  outer  zone  of  the  disk.  As 
it  comes  forward  towards  the  lens  its  contour 
resembles  that  of  the  Bald  Eagle. 

This  fundus  is  singularly  free  from  opaque 
nerve  fibres. 

Bald  EAGr.E.  Ilcdiaetus  leucocephalus. 
The  fundus  picture  seen  in  Plate  XXXIH, 
page  133,  is  the  result  of  an  examination  of  a 
number  of  individuals.  The  writer,  for  ex- 
ample, had  an  ophthalmoscopic  view  of  the 
eyeground  of  five  Bald  Eagles  in  the  Bronx 
Park  collection. 

The  prevailing  color  of  this  bird's  fundus  is 
dark  reddish-brown,  the  lower  half  changing  to 
a  dull  orange-red.  The  whole  eyeground 
is  covered  with  choroidal  '•apillaries,  and 
dotted  over  with  brown  pigm..it  grains,  giving 
it  a  rough,  granular  appearance.  A  gray 
sheen  pervades  the  upper  part  of  the  fundus. 
On  the  temporal  side  and  some  distance 
from  the  upper  end  of  the  optic  nerve  is  a 
brilliant,  white,  round  dot  surrounded  by  a 
small,  light-green  reflex  ring,  which  is  itself 
enclosed  in  a  very  br-lliant,  narrow  green 
ring  —  the  muscular  region.  On  the  nasal 
side  of  the  disc,  and  on  a  lo'al  with  this 


THE  FT'XDI'S  APPEARAXCES  IN  VARIOUS  ORDERS  OF  BIRDS 


01 


tnnriila  is  another  iircn,  of  a  fpray  color,  siir- 
roiiiidfil  hy  a  fiin-shapcd,  luminous  reflex. 

The  optic  ncrre-fniranre  is  distinctly  white, 
niid  along  its  center  is  strewn  a  large  luimher 
of  minute  pigment  dots.  The  outer  margin 
of  the  liisc  is  bordered  with  l)Ia<'k  pigment, 
as  if  a  shadow  were  cast  upon  it  liy  llie  [K'eten. 
In  this  regard  and  in  sonic  olliers  this  fundus 
resemhles  the  eyeground  of  the  Sea  Eagle. 

WiiiTE-BKLMKD  Se.\  EAfiLi;.  Ilaliaetus 
lencoijaskr.  The  ocular  fundi  of  three  in- 
dividuals of  thi .  siK'cies  were  found  to  he  iden- 
tical and  furnis.i  the  oi)hthalmoscopic  appear- 
ances shown  in  Plate  XXXIV,  page  1.5,'5. 

The  rolnralion  of  the  eyeground  is  mostly 
dull-l)rown,  the  lower  quarlrants  of  the  field 
being  covered  with  dull,  orange-red  capil- 
laries evidently  choroidal. 

The  optic  di.ic  is  a  long  white  oval,  whose 
center  is  tinted  with  oran)^>  and  covered  with 
tiny  pigment  dots.  The  papillary  margins 
arc  white  bordered  with  black  pigment. 

The  upiK-r  half  of  the  fundus  is  covered 
by  a  mass  of  dull  gray  dots.  There  is  a  well 
defined  reflex  near  both  maculae,  each  similar 
in  position  to  that  seen  in  the  Kestrel.  These 
areas  are  evidently  very  sensitive  to  light,  as 
the  bird  becomes  very  fidgety  and  irritable 
when  the  reflected  rays  from  the  mirror  are 
thrown  directly  o!i  one  or  other  fovea. 

The  pccL'ii  is  very  large  and  comes  well 
forward  towards  the  posterior  surface  of  the 
lens.  Both  extremities  of  the  organ  are 
clearly  visible  through  the  ophthalmoscope. 
There  are  very  opaque  nerve  fibers  to  be  seen 
in  any  part  of  the  eyeground. 

American  Osprey,  or  Fish  Hawk.  Pan- 
dion  halia'.ivn  carolinensis.  When  light  is 
thrown  directly  from  the  front  and  at  a  dis- 
tance of  one  foot,  on  the  pupils  of  this  bird  of 
remarkable  visual  powers  the  red  reflex  is 
scon  to  occupy  fully  three-fourths  of  each 
pupillary  area. 

By  the  aid  of  the  ophthalmoscope  the 
writer  found  the  general  funded  coloration  to  be 
bluish-gray  with  a  suggestion  of  brown. 
These  tints  are  uniformly  distributed  through- 
out the  ocular  background,  and  there  is  very 
little  of  the  striation  seen  in  Duteo  and  other 
genera. 


The  pecten  almost  entirely  obscures  the 
view  through  the  pupil  of  the  optic  disc;  it 
is  a  compact,  intensely  black  body,  showitig 
about  ten  convolutions. 

Mainly  because  of  the  undilated  pupil  and 
large  .>ecten  no  definite  fovea  was  visible. 

EinopKAN  Kestiiel.  Tiiiiiiiiiciihis  ahiu- 
darina.  Plate  XXXV,  page  15.5,  is  a  faithful 
reproduction  of  the  ophthalmoscopic  appi.'ir- 
anees  in  this  sharp-sighted  species,  depicting 
the  right  eye  by  the  direct  method. 

The  ground-color  of  the  fundus  is  a  light 
brown,  or  brownish-gray.  The  l;)wer  quad- 
rants are  streaked  with  orange-red,  choroiilal 
capillaries  that  run  in  a  more  or  less  vertical 
direction,  an«l  become  more  distinct  ami 
brighter  ri'd  as  they  approach  the  pt'iphe.-y 
of  the  field.  The  optic  disc  is  a  long,  white 
oval,  showing  its  margins  well  beyond  the 
pigmented  and  fringed  pecten.  The  central 
area  of  the  papilla  appears  to  be  hollowed  out 
like  a  canoe  and  the  pecten  does  not  overlap 
it  at  any  point  of  its  cireumference,  as  is  so 
frequently  the  case  in  avian  fundi. 

The  disc  extends  as  far  downwards  towards 
the  fundal  periphery  as  the  observer's  eye  can 
reach.  At  its  lower  extremity  several  small 
ehoroid.il  vessels  can  be  seen. 

The  pecten  has  a  rounded  but  pyramidal 
form,  sloping  towards  the  centre  of  the  disc 
at  both  ends.  It  is  of  a  dull-brown  color,  and 
corrugated  like  a  photographic  camera.  At 
the  junction  of  pecten  and  papilla  are  scat- 
tered numerous  brown  dots,  so  disposed  as 
to  give  the  former  the  appearance  of  a  web. 
The  upper  part  of  the  eyeground  is  quite 
devoid  of  choroidal  blood-vessels,  but  is 
covered  with  minute  white  dots.  The  fundus 
is  much  clearer  of  the  retinal  shimmer  or  re- 
flex noticed  in  most  birds. 

The  two  macular  regions  are  very  distinctly 
visible.  The  nasal  macula  is  situated  just 
above  the  upper  end  of  the  disc  and  about 
half  a  disc-length  on  the  inner  or  beak  side 
of  the  eyeground.  It  is  a  dark-brown  spot 
with  a  pale  area  all  around  it.  Outside  of  this 
region  and  enclosing  it  are  two  distinct,  pale- 
green,  filiform,  reflex  rings,  the  interior  rings 
being  quite  free  irom  the  white  dots.  On 
the  outer    aspect  of    the  eyeground,  about 


09 


THE   FUNDrs  OCILI  OF  BIRDS 


«mo-tliir<I  f hi-  lenRth  of  flu-  disc  nl)ovo  nn<l  two- 
thirds  to  ilfi  outer  siilo,  is  st-on  thi-  sf-cond  or 
t(-nipornl  nin(-uhir  n-Kion.  At  its  ((-nlcr  is  u 
li«lil.  limy  spot  surrounded  l)y  a  dark  hrowii 
area.  Both  these  area-  are  in  their  turn 
enrirelod  hy  a  small,  pnle-green,  reflex  rins 
about  one-fourth  the  diameter  of  the  corrt-- 
spoiiding  circit-  about  the  superior  macula. 
Sl(-nder,  opaque  nerve  fibers  run  out  at  ri^ht 
angles  to  the  disc  on  both  sides. 

Hkd-tailkd  Hawk.     HuIco  borcalia.     The 

f)/)/iV-«<T(r r/f/rrtwrc  in  the indiviiluals  examined 
by  the  writer  is  almost  entirel,<-  covered  by  the 
prrleii,  except  at  its  superior  end.  which  can  be 
outline(l  and  examined  by  tin  mirror.  It  lies 
(obli(iuely)  at  an  angle  of  about  70  degrees  with 
the  upper  mandible,  and  can  be  seen  through 
the  more  or  less  translucent  pecten.  The  back- 
^.ound  generally  has  a  striated  npp«-arance 
with  the  choroidal  ves.sels  showing  through. 

Little  Bistahd.  Te  ix  Mrax.  Plate 
XXXNI,  page  155,  reprodues  the  left  fundus 
oculi,  direct  image,  of  this  species.  The 
fundal  coloration  is  mostly  a  warm  gray, 
covered  with  small,  dull  orange-red  dots.  In 
the  lower  half  of  the  field  and  on  each  side 
of  the  optic  nerve  entrance  is  a  number  of 
choroidal  blood-vessels  of  a  dull  oran^je-red 
color,  running  parallel  with  the  disc. 

So  far  as  seen,  the  papilla  is  a  dead  white; 
optic  fibres  form  a  fringe-like  setting  about  it. 
The  central  zone  of  the  disc  is  covered  by  a 
mass  of  minute,  brown,  pigment  deposits  of 
irregular  shape.  Opaque  nerve  fibres  extend 
at  right  angles  to  the  disc  on  either  side. 

A  little  to  the  temporal  side,  about  one 
disc-lengtb  from  the  upper  end  of  the  optic 
nerve,  is  a  small,  brown  spot  like  a  tiny  hole. 
This  macular  area  is  surrounded  by  a  brilliant, 
green  reflex  ring. 

The  pecten,  of  a  dark  chocolate-brown  color 
;ind  shaped  like  a  corkscrew,  comes  well  for- 
ward towards  the  inferior  border  of  the  lens. 
The  fundus  of  the  Great  Bustard  ~  0/("« 
tarda  —  closely  resembles  that  of  0.  tetrai. 

Strigifonu  ., 
T    \NT  Owl.     Syrnium  alticn.     (Figs.  132 
and   96).     The    ocular    background   of    this 
species    shows,   macroscopically,   a    solitary. 


tempiiral,  macular  region  and  fnrea.  This 
single  macidar  area  is  about  a  disc  length  and 
a  half  abov«-  and  to  the  temporal  side  of  the 
smaller  or  sup«-rior  end  of  tlu-  pt-cten. 

The  irrt-gtdar  shnp«-  of  the  (-yeball  and  fun- 
dus in  the  Owl  must  not,  in  this  connection, 
be  forgotten.  The  comparatively  undersized 
prclen  exhibits  14  convolutions  (four  large 
and  of  equal  size,  ten  unequally  snudlerj  that 
when  viewt-d  from  abov(-  look  like  a  small 
bunch  of  raisins.  Between  the  folds  may 
Ik-  seen  the  margin.s  of  the  optic  nerre  en- 
trance. The  crest  surmounting  the  upper  free 
border  is  very  thin,  inconspicuous  and  unde- 
veloiK-d. 

The  nphlhalmoncopic  ricir  of  the  normal 
fundus  (the  result  of  examination  of  numer- 
ous individuals)  is  shown  in  Plate  XXXVII, 
page  157. 

On  the  outer  asp<-ct  of  the  papilla  and 
about  one  disc  length  from  it,  on  a  kvel  with 
the  uppi-r  margin  of  pt-cten,  is  a  slight  de- 
pression   (macula)    alnunt    devoid    of    cho- 
roidal vessels.    Its  centre  is  a  dark  red  color, 
the  whole  macular  region  closely  resembling 
the  same  area  in  the  (brunette)  human  eye. 
On  the  margins  of  this  depression  and  sur- 
rounding it  is  a  bright  circular  reflex.    Head 
found  this  reflex  to  be  so  bright  and  dense  in 
some  individuals  that  it  was  difficult  to  see 
the  other  macular  details,  although,  in  most 
instances,  by  shifting  slightly  the  reflected 
rays  from  the  mirror  the  macular  margins 
come  out  distinct  and  sharp.    For  some  dis- 
tance outside  this  foveal  ring  the  eyeground 
is  seen  as  if  on<-  were  viewing  it  through  a 
translucent,  grayish  mist  or  haze;  and  the 
fundus   thus   seen   generally   appears   to   be 
granular  with  a  few,  small  choroidal  capillaries 
showing  here   and   there.    Inside   the   ring, 
however,  the  details  are  .strikingly  clear,  and 
the  coloration  bright  red.    Above  the  macula, 
in  the  outer  side  of  the  disc,  is  a  quantity  of 
dark   pigment   deposited   between   the   cho- 
roidal vessels,  l.y  contrast  making  the  latter 
stand  out  as  of  a  bright  orange  color.    The 
inner  aspect  of  the  fundus  appears  yellow;  it 
exhibits    numerous    choroidal    blood-vessels, 
whose  yellow  tint  is  distinctly  brighter  near 
the  inferior  segment  of  the  disc. 


THE   FTXDIS  APPEARANCES   IN  VARIOlS  ORDERS  OF  BIRDS  OH 


1 


Fig.  13i.     Tawny  Owl  {Syrnium  alum)  x'l. 


Fig.  133.     Greater  Siilphur-crested  Cock.''»oo  (Cacatiia  galerila)  X9. 
Macroscopic  Appearances  of  the  Fundus  Oculi  in  the  Preserved  Eyes  of  Birds. 


i 


§4 


THE   FlNOrs  (K-rU   OF   BlltfJS 


ntmioxviNO     Owi..       Sftrnli/to      nil 
hjipogtrn.    The  twiiljir  fiiinlii.i  nt  this  .>.|h« 
irr«'«iilnrly   roiiml,   iis    in   nil   lli<-  Owl*,    iixl 
ill  pnpiirrd  s|M(iiiitns  I  In-  .UlaiU  sli.iw  <|is- 
linrlly. 

Tlic  single,  tcinpornl,  oviil  miirnlnr  rrgioi. 
lies  iiliovi-  nnil  nhoiit  a  ilisc  IciiKtli  anil  a  half 
from  Ihi-  up|XT  <ii<l  of  lln-  papiHa.  In  Ihf 
rt'nfer  of  thi-  niariila  is  flio  fovea  —  a  ilark 
pitfiiifiKcil  spot  «ifli  fiiif  granule!*  arran^'.'il 
rap-like  aliovc  it.  Outside  this,  iiftain.  •■,  the 
ovoid  circuinferinee  of  this  region,  'iirom- 
pletely  edsed  with  fine  dots.  These  art  more 
ni'.iieroiisly  distriltiited  Ik'Iow  the  macula 
than  above  it.  C  >nne<t  d  with  tin  maeiilar 
i-eRion  is  a  ji^ht  colored  and  rather  liroad  hniid 
that  extends  horiitontii  y  to  the  center  of  the 
visil.lv-  ImckKroiind.  It  is  unevenly  divided 
into  two  strips  liy  a  parallel  arrangement  of 
minute   pitrnient    dots. 

Seen  from  ahov-  the  relatively  small  /xv/ch 
closely  resemhli  s  a  disarticulated,  acumiimte 
leaf,  the  stem  repre-'-ntiiiK  tin  spinous  pro- 
jection immediately  ai,ove  tin-  lowest  terminal 
convolution.  The  light  doutile  folds  of  the 
marsiipium  .sIoim-  backwards  and  cover  most 
of  the  optic  entrance;  they  meet  above  in  a 
uniform,  very  narrow,  .slightly  undnlatinj? 
crest  who.se  posterior  end  i)rojecls  half  the 
li'-ight  oi'  .he  unlyinj?  coil  well  into  the  vitre- 
ous cavity.  An  extension  upwards  of  thi 
Ions  axis  of  the  disc  cuts  the  retinal  band  at 
till'  junction  of  the  inner  and  second  fourth, 
making  an  infiilapapillary  angle  of,  perhaps, 
40°. 

This  interesting  Owl  is  cspt>cially  subject, 
like  other  .Strigifornies,  to  pathological  varia- 
lion.s  in  the  fundus  picture  due  to  confinement 
and  domestication.  Both  Head  and  the 
writer  examined  a  nuni'cr  of  individuals  that 
undoubtedly  exhibited  choroidal  di.se-se  and 
other  pathological  changes.  Rejecting  these, 
the  p'lieral  color  of  the  fundus  of  this  species  is 
found  to  be  dull-orange,  mottled  and  blotched 
in  its  upper  half  with  orange-red.  Choroidal 
vessels  are  plainly  seen,  covering  all  the  lower 
part  of  the  eyeground,  just  as  in  the  Tawny 
Owls.  The  well  defined  macular  area  is  .seen 
within  tl  e  outer  half  of  the  f;i.idu.s,  a  little 
above  the  upper  extremity  of  the  optic  disc. 


It  is  distinguished  from  the  surrnundinK  cho- 
roid by  a  collection  of  minute  pigment 
grannies  or  dot.s  with  n  brigh?,  while  .spot  in 
their  centre. 

The  opilr  di.w  is  white  and  of  oblong  shapj , 
slightly  rounded  at  the  ends.  From  its  ••dgcjt 
run  a  few.  short  nerve  fih.es  that  form  a  com- 
plete fringe  about   the  visible  papilla. 

Tin-  ptrtrn  is  decidedly  larger  in  proportion 
to  l)odily  measurements  than  one  finds  it  in 
most  of  the  larger  Owls,  espe<ially  larger  than 
in  the  Tawny  Owl.  It  exli-iids  well  forward 
into  the  vitreous,  and  its  lower  half  ai)p<'Hrs 
very  massive  and  of  a  dark  brown  color.  The 
jM-ctinate  coii.oliitions  are  ph'.inly  seen  and 
the  anterior  or  iippt-r  half  is  more  delicate  in 
si  met  lire,  being  jMrforatid  where  it  joins  the 
disc.     Here  it  forms  a  dark  network  on  the 

siirfat f  the  nerve-head  whe— ,  also,  a  few 

red  granules  mingle  with  the  cho<'olatc-bruwn 
texture  of  the  |H'cten. 

Snowy  Owi,.  Sijvlea  ri'-tra.  It  is  a  popu- 
lar belief,  and  one  held  in  many  public 
aviaries,  that  ihese  owls  are  likely  to  become 
blind  if  much  exposed  to  daylight,  ("on.se 
(|uently  they  are  often  caged  in  darkness  or 
semi-darkness,  although  their  habits  are  really 
diurnal,  or  at  least  th'-  an  as  much  Day 
birds  as  Night  birds. 

In  any  event  the  ch  inges  in  habitat  in- 
volved in  their  captive  surroundings  arcs  in 
Hie  judgment  of  the  writer,  responsible  for 
iTi'ain  alterations  found  in  their  fundi  and 
in  those  of  other  Hubonidae  kept  for  more 
than  a  >"ar  or  two  in  pubi'c  gardens. 

The  II  (rnial,  dominant  coloration  .,j  thi 
fundus  is  very  light  yellow-red,  but  de- 
cidedly less  reil  than  in  Symium  aluro.  See 
Plate  XXXVH,  page  157,  of  this  Atlas.  In 
the  first  individual  (two  years  in  captivity) 
examined  there  were  throughout  iheleft  lack- 
ground  extensive  choroidal  changes,  e.spec'-lly 
one  cruciform,  pigmented,  partially  aln,.  no 
area  running  across  the  field  towards  the 
nasal  side.  These  long,  st.-iated  alterations 
were  also  seen  in  the  temporal  part  of  the 
fundus. 

The  large,  club-shaped  pccten  springs  from 
a  well  defined  whitish,  ovoid  di.«c.  The  mar- 
gin of  the  papilla  is  occupied  by  nu.Tierous 


TIIK    FINms  .\I'I'KARAN(  FS    IN    \  AHHHS  ()Hr)FHS  OF   BIIIDS 


IM 


ftiiiiill.dotli'il  ;ii«nnnt<<l,l.'i).>»it«.     Tli«<Miiliir 
iiii'iliu  Wire    iilirclv  <  Icnr. 

In  the  riijhl  fitiiiliii  tin-  |)iitli<ilii);ii'.'i|  cliiiiijfcs 
wiTi  (lif  Mime  cxcciil  tliiil  linviiri'N  llii  niisiil 
siilr  uf  the  piipillii  then-  .-  a  liiri{c,  jitri)|iliic, 
liiKiiK'iilfil  uri'ji  cxtfriiliii;,'  ;ilriiost  o  tin- 
(MTiplicry  of  tlic  f;iri<lu^,  «iitirt|y  iililik"  the 
sriijilliT  iirid  iiarritivcr  loioii  in  tlif  left  cyi'. 
Alt'i>;cllicr  the  inorl>ii|  cliiiiiKrs  in  the  ri>;ht 
<•>•(•  lire  inori-  niiiiHTiiiis  tluiii  in  tli<-  left. 

li  a  yoiiiiffcr  iniliviiliiiil  tlic  (oinratioii  of 
I  Ik-  hack^ro  iii.l,  the  i»apilla.  tho  |Hclfn  nnd 
thf  iiiaciilar  r<"j;ion  were  precisely  as  in  tie 
firsl-nienijoned  hird.  The  pathological  N-- 
sions,  however,  were  entirely  (litFerent.  They 
appeared  in  each  eye  as  four  or  five  rather 
sniall.  round,  pijfnienled  exudates,  having  a 
whitish   atrophic-   (?)   centre,   much   iiKc   tho 

I linni-sized    deposits    in    the    human    «'yi" 

when  alfected  hy  a  <lisseminatcd  choroi<litis. 
Fi  ioi'K.w  Haiin  Owl.  SIrix  flnmmca. 
(Figs.  97  and  IN;  macroscopic  view).  This 
fundi!-  shows  the  .single  s«'iisitive  regioti.s 
iiiiiinilii  anilfomi)  on  the  temimral  aspect  of 
the  field,  slightly  above  and  les.s  than  the  long 
ilisc-diamcter  from  the  upfwr  t«  nination  of 
till'  optic  entrance.  The  fovea  is  represented 
hy  a  large  dot  in  the  center  of  a  number  of 
minute  granules,  surrounded  by  an  u. 'tinted 
ari'a  incloseit  in  a  ring  of  still  more  numerous 
pigment  grains. 

The  snudi  pcrlcn  is  made  up  of  U  sHo-*, 
stout  convolutions  (the  largest  ten  of  equal 
size)  thai  only  partially  cover  the  nerve  head, 
which  has  pignie  t  granules  scattered  over 
its  surface.  The  pectinate  coils  meet  above 
and  are  j  lined  by  a  straight,  thin,  cord-like 
crest.  Th  /  all  incline  towards  the  posterior 
free  border.  The  upper  free  margin  is  about 
half  the  length  of  IIk  papilla. 

The  fundus  oeuli  of  the  British  species, 
painted  from  a  recently  captured  specimen, 
is  depicted  on  Plate  XXXVIII,  page  157. 
With  Mr.  Head,  the  writer  examined  many 
of  the  Stri^idn;  confined  at  the  time  (July, 
lf)12),  in  the  gardens  of  the  (British)  Zoolog- 
ical hoeiely.  Those  that  had  bee-  caged  two 
yi.irs  or  more  were  plainly  affecttil  with 
choroidal  changes,  mostly  of  the  disseminated 
choroiditic  typ<>,  the  choroidal  atrophy  and 


pijriiient  de|)osits  v.irying  in  iniount  but 
nciirly  always  niori-  marked  thi"  longer  the 
birds  had  lieeti  imprisoned. 

The  gemrul  luiiv  iif  lit,  ii/i  finiitnil  in  .S7n>- 
flitmmea  i.o  dull  -ray  with  bright,  clearly  out- 
lined, orange  i(d  choroidal  vessels  distributed 
all  over  the  fundus,  except  at  the  macular 
rej;ion.  At  this  area  the  lint  is  much  gr.iyer, 
Ining,  in  addition,  stifipled  with  snuill,  irregu- 
lar blotches  of  oran^'e-r«'d  and  gray  ilots. 

The   macula  is  also  sulfused   with   a   gray 
rellcx.     It  is  situated  above  the  i'    ■>«t  end  of 
the  optic  disj-  and  nearly  in  a  hue  with  th' 
long  axis  of  that  rirgan. 

The  papil'a  is  long  and  narrow,  wil  li  pointed 
•■nds,  and  is  apparently  made  up  d  coarse, 
white  fibre-bundles  the  central  portion  of 
which  is  coven'd  with  minute,  iirown,  pig- 
ment grains,  that  have  a  distinctly  reticulated 
apiK-aranci'.  These  white  fibres  bonhr  the 
nerve-head  all  around. 

The  dark-brown,  convoluted  pectcn  of  the 
Barn  Owl  is  nuich  larger  than  that  of  the 
Tawny  Owl.  It  is  also  placed  farther  for- 
ward towards  the  lens  than  the  pectcn  of  the 
latter  bird.  Fxtending  from  both  sides  of 
the  di.sc  are  a  few,  dull-gray  fibres  that  stretch 
a  short  di-tance  acro.ss  the  fundus  and  then 
di.sapjM'rir. 

Two  iK'cimeus  of  Slrir  pratinmla  and  two 
of  Strij-  perf^a  revealed  ophthalmoscopic 
appearuiKO  <|i«ite  -  nilar  to  those  .seen  in 
Strix  flan,  ,i.  ,  sc  |  |,at  the  fundi  of  the 
two   first    lanied  -es   ai.     generally   of   a 

deeper    grii,\       All       ..ese    (four)    individuals 
wen-  suffering  f-nm  *  !«oroidal  changes. 

P'  fo'~mes 

GuE.\T       Su.-t  .)       Cock -TOO. 

Cacaliin  gilerifa.  ;ind    .33;    mac- 

roscopic view-,  i     i^         •<  M,  iilar  backgrouiu/ 
there  is  no  visible /«»      ir  macular  area. 

The  niedium-size<i  '-ieii  exhibits  rather 
broad,  rotiniled  coin    I  s  -oiiie  24  iii  alf, 

that  arc  joined  abov  hea\      process  or 

crest  of  irregular  outlm.  »»  latl«  <  extend*' 

one-half  the  length  i.i  xh-  upper      irflcr 

joining  together  nine  e<|UHi   .t&    4">»bl.-  fold* 
From  this  keel-like  body  tht  m^  *h'  p<->- 

ten  slopes  ofl  to  the  froUi,  e«  -rtir. 


IMI 


THE   Fr\nUS  OCl'LI  OF  BIRDS 


n(  llic  wliili»li  iii'tvr  lii-ail,  which  \*  tloltfil 
with  Very  >tniill  |iit(nii-nl  unttiiilo. 

Thi-  i)i>hthiilini>/iriti>ir  ri/>/«(ir(iMrc,«  of  th''  li'ft 
<\vi'  of  Ciiraliitt  giilrrila,  vwrt  itiiiip',  iin"  |Mir- 
lr.i.V.<l  in  ri,.t.-  XM,  imgc  l«l.  The  Ixirk- 
ijriiiiiKl  i^  of  ii  fairly  uiiiforiii,  11^1)1  Krayixh-lihii- 
color,  sprinkled  with  iiiitiiitc  white  dots  that 
arc  iiilcr«|)«'r'«<il  with  niiiiiy  whh  iiiiiiicroiM 
liiit  soiia-wlial  larKcr  dark  ^ray  dc|>o»it!i. 
The  macular  ana,  at  the  ii|>|M'r-iniicr  <|uad- 
rnnt,  i*  nii  irrcnularly  round,  liiifht  brownish 
area  whose  diameter  i<t  half  tlie  disc  lenjfth. 
It  is  not,  as  in  many  Birds,  surronnded  and 
defined  hy  an  outer  rinjj;  the  jM-ripliery  fades 
into  the  :  iirrountlmK  ^ray  of  the  fundus.  The 
up|M-r  sixth  of  the  long,  pointed  papiUa  is 
ilislinclly  visilile  where  il  is  not  covered  liy 
the  indented  perlcn,  whose  twelve  doutile  folds 
have  a  corkscrew  termination  altovc.  I'or- 
tions  of  the  disc  liorders  can  !><•  M'cn  from 
aliii\e  through  the  plications,  except  at  its 
posterior  terminal  where  the  dark-hrown  nuiss 
entirely  covers  it.  Knint,  wiiitish  lines  of 
opacpie  nerve  fibres  extend  from  the  nuirKin.s 
of  the  upper  half  of  the  disc  n  short  distance 
across  the  ct-ntre  of  the  eyeground. 

OiUNOE-wiNCED  Parrot.  Chnjunlin  ama- 
zona.  I'late  XXXFX,  page  159,  n'presents 
the  ophthalmoscopic  appearances  in  the  right 
eye  of  this  species.  The  dominant  color  of 
the  iijeground  is  deep  gray  tinted  with  buff. 
The  lower  sectors  ar  ;ho  p«-rii)heral  zone 
of  the  fundu'  are  >i  if  used  with  pink,  the 
background  generally  l)eing  punctuated  with 
minute,  duM-yellow  dots. 

The  macular  area  is  situated  towards  the 
nasal  side  of  the  disc,  a  little  above  the 
end  of  the  pectcn.  It  is  slightly  depres.sed 
an.l  enclosed  by  u  rather  bright  but  pale-green 
reilex-ring.  Extending  from  the  circum- 
ference of  this  circle,  slightly  above  as  well  as 
below,  are  a  few  translucent  fibres,  pale 
gnn-n  in  tone;  and  at  its  centre  is  a  dark- 
gray  dot  or  depression,  with  a  small,  faint 
halo  extending  from  its  upper  edge. 

The  optic  nerre-head  looks  as  if  it  were 
composed  of  coarse,  white,  opatiue  fibres, 
which  form  a  fringe  all  around  the  deeply- 
colored  jx'cten.  The  papilla  is  long  and 
boat-shaped,  and  its  outlines  can  be  traced 


the  whoh-  length  of  the  pecten.  Many  f5n«», 
gray,  opaque  nerve  fibres  extend  from  the 
■iiurgins  of  the  papilla,  cross  the  bickground 
I  f  the  eye  and  un;  eventually  lost  in  the 
fundal  tissues. 

The  dark-brown  perien,  MfU  from  -"Imve, 
has  a  spiral  form,  with  n  tag  or  tail-piec<<  at 
the  upixr  end.  A  lateral  view  shows  it  to 
Ih-  plicated,  like  a  fan.  It  stands  well  forward 
towards  the  lens. 

The  light  reflected  info  the  eye  from  the 
ophlhalnioscopic  mirror  does  not  a(>pt>ar  to 
disturb  s|M'cimens  of  the  s|H-cies  .it  all, 
uidess  it  is  concentrated  on  the  macular 
region. 

White-fronted  Ci'ban  Coniire.  (?) 
Conurun  ridgu-ny.  The  writer  examined  with 
tlie  ophthalmoscope  the  fundi  of  an  individur 
four  years  old  that  had  Ixtm  an  inmate  of 
Bronx  Park  for  three  months.  Neither  a 
one-fifth  of  one  |H'r  ot'nt  soLition  of  sulphate 
of  atropia  nor  a  homatrophine  and  cocaine 
mixture  had  any  effect  on  the  size  or  motility 
of  the  pupil. 

The  eyeground  was  generally  reddinh- 
gray;  the  pecten  was  large,  convoluted  and 
extended  well  into  the  vitreous  cavity  and 
approached  the  posterior  lens  surface.  There 
was  no  , ell-defined  macular  regie  I.  The  op- 
tic entrance  was  almost  covered,  and  a  viev,- 
of  it  obscureti,  by  the  base  of  the  pecten. 

Kakapo.  Owl-Parrot.  (New  Zealand.) 
Stringopn  habroptilus.  In  July,  1014,  the 
writer  examined  the  .single  specimen  then  in 
the  gardens  of  the  Zoological  Society  at 
Regent's  Park,  London.  The  bird  had,  at 
that  date,  l)een  in  captivity  two  years,  and 
seemed  dazed  when  exposed  either  to  bright 
natural  or  artificial  light.  The  keeper  reported 
that  the  bird  is  very  quiet  during  the  daytime 
but  digs  in  the  sand  of  bis  box  at  night.  The 
lids  have  no  cilia-like  protection — only  scat- 
tered plumules  on  the  otherwise  naked  lids. 
He  has  large  pupils  and  a  dark  brown  iris. 

The  red-brown  fundus  is  fairly  easily  seen 
with  the  ophthalmoscope  without  using  any 
mydriatic.  The  frontal  position  of  the  eyes 
(found  in  all  Strigiformea  and  to  which 
order  the  writer  believes  this  species  right- 
fully belongs)  is  marked  in  this  animal,  and 


TIIK   KINDIS  .VIM'K.VHA.\(  KS   rs    V.MiUMS  OUDKUS  OF   BIHDS 


07 


I 


Fip.  135.     Anna  Hummingbird  {Calypte  anna)  ;<31. 
Macroscopic  Appearances  of  the  Fundus  Oculi  in  the  Preserved  Eyes  of  Birds. 


J 


08 


THE  FUNDUS  OCULI  OF  BIRDS 


the  bird  evidently  possesses  binocular  vision 
as  he  always  looks  straight  ahead  at  objects 
that  he  wishes  to  see  distinctly.  Plate  XL, 
page  159,  furnishes  an  ophthalmoscopic  view 
of  the  right  eye,  erect  image.  The  eye- 
ground  is  orange-red  stippled  all  over  with 
lighter  orange  dots.  The  lower  half  of  the 
fundus  has  a  large  number  of  minute,  dark, 
reddish-graj'  depots  of  pigment  intermingled 
with  lighter  dots;  also,  a  great  many  cho- 
roidal blood  vessels  run  in  a  vertical  direction 
over  the  field  of  view  on  either  side  of  the 
optic  entrance.  They  become  more  numerous 
towards  its  lower  periphery. 

The  macula  is  placed,  as  in  Owls  generally, 
on  the  temporal  side  of  the  optic  papilla, 
about  one  disc-length  from  its  upper  end 
and  half  that  distance  to  the  temporal  or 
outer  aspect  of  the  fundus.  It  is  a  bright, 
orange-red  area  surrounded  by  dark,  red- 
gray  pigment,  like  a  shadow.  There  is  no 
circular  sheen  around  it,  such  as  has  been 
noted  about  other  avian  foveee. 

The  optic  nerve-head  is  white,  and  along 
its  center  appears  a  network  of  minute, 
brown  pigment  dots  clustering  around  the 
sides  of  the  jjecten.  A  few  white  opaque 
nerve  fibres  extend  a  short  distance  on  either 
side  and  about  the  upper  end  of  the  disc. 

The  pecten,  of  the  u:ual  black-brown  color, 
extends  the  whole  length  of  the  disc.  It  is 
rather  straight  in  its  upper  half  but  is  more 
convoluted  towards  the  lower  part,  where  it 
is  quite  massive  and  resembles  a  corkscrew. 
This  portion  of  the  pecten  comes  markedly 
forward  towards  the  lens  so  that  it  more 
nearly  resembles  the  same  organ  in  the 
Burrowing  Owl  than  in  the  Parrot ;  as  indeed 
the  foregoing  studies  of  the  fundus  oculi 
lead  unmistakably  to  the  conclusion  that 
this  bird  belongs  to  the  Owls  rather  than 
to  the  Parrots. 

Coraciiformes 

European  Kingfisher.  Alcedo  ispida. 
(Figs.  99  and  113;  macroscopic  view.)  This 
remarkable  background  .shows  two  exten- 
sive, well-defined,  circular  macular  regions, 
both  supplied  with  a  large,  deeply  pigmented 
fovea.      The    nasal    macula    is    large    and 


saucer-like.  The  Jmea  nasalis  is  surrounded 
by  a  nebula  formed  of  microscopic  dots 
thai  are,  however,  absent  at  the  lower 
nasal  third  of  its  margin.  About  the  same 
distance  down  and  temple  wards  from  the 
superior  end  of  the  disc,  as  the  deeper  fovea 
is  up  and  nasalwards,  lies  the  secondarj'  area 
temporalis.  [In  the  sketch  the  wall  of  the 
globe  is  cut  away  to  expose  it.]  This  tem- 
poral macular  region  is  smaller  and  not  so 
well  defined  as  the  nasal  fovea  but  it  exhibits 
a  distinct  pigmented  centre  surrounded  by  a 
dotted  ring. 

The  large  and  curious  pecten  exhibits  17 
double  folds,  two  at  the  superior  terminal 
of  the  organ.  These  34  convolutions  are 
very  thin  (like  strips  of  paper),  and  through 
the  wide  intervening  spaces  almost  the 
whole  surface  of  the  optic  disc  can  be  seen 
and  its  outlines  readily  traced.  The  papil- 
lary surface  is  dotted  exactly  like  the  sur- 
rounding retina.  The  crest  or  free  border 
of  the  pecten  is  quite  narrow,  and  caps  the 
pectinate  mass  in  a  wavy  line.  The  naked- 
eye  view  from  above  gives  a  picture  much 
like  a  fern  frond. 

Laughing  Kingfisher.  Dacelogigas.  The 
ophthalmoscopic  appearances  of  this  species 
are  pictured  in  Plate  XLII,  page  161. 

The  fundus  oculi  is  in  general  of  a  light 
fawn-gray  color  mingled  with  irregularly 
shaped,  white  or  gray-white  dots,  except  in 
the  neighborhood  of  the  optic  nerve  where 
it  is  orange-red,  like  the  glow  cast  on  the 
sky  by  the  setting  sun. 

The  optic  nerve  entrance  is  long  and  narrow; 
it  is  white  except  along  it  -  central  area,  which 
is  orange-red  striped  with  brown  pigment 
dots.  A  large  number  of  opaque  nerve 
fibres  run  out  on  each  side  of  the  optic  nerve 
and  at  right  angles  to  it. 

The  pecten  is  very  long  and  narrow  and 
has  the  appearance  of  a  brown  centipede. 

The  macula  is  very  conspicuous.  About 
half  a  disc-length  from  the  upper  end  of  the 
nerve,  towards  the  nasal  side,  is  a  small, 
round,  dark-brown  hole,  surrounded  by  a 
very  narrow,  bright  green  ring.  This  circle 
encloses  a  smaller  area  that  is  of  a  darker 
gray  and  devoid  of  the  dots  seen  at  other 


THE  FUNDUS  APPEARANCES  IN  VARIOUS  ORDERS  OF  BIRDS 


!)!) 


Fig.  137.     Red-.sbafted  Flicker  {Colaptes  mexieanus)  X  li. 
Macroscopic  Appearances  of  the  Fundus  Oculi  in  the  Preserved  Eyes  of  Birds. 


is:..si 


100 


THE  FUNDUS  OCULI  OP  BIRDS 


parts  of  the  eyeground.  The  forca  na/ialis 
always  appears  directly  opposite  the  pupil; 
there  is  no  fovea  iemporalis  visible  to  the 
ophthalmoscope. 

Common  Hoopoe.  Upupa  epnp.i.  (Figs. 
134  and  100;  macroscopic  view.)  This  niedi- 
iiin-tinted  fundus  exhibits  a  .single  macular 
region, — a  round  figure  whose  diameter  is 
equal  to  the  extreme  width  of  the  papilla. 
It  is  depicted  by  a  dotted  line  of  pigment 
grains  that  are  more  numerous  below.  The 
forea  is  shallow  and  not  well-defined. 

The  relatively  large  pecten  has  numerous 
(about  40)  convolutions;  it  forms  a  compact 
mass  that  almost  obscures  the  papilla,  par- 
ticularly when  the  disc  is  viewed  from 
above.  It  is  covered  by  an  ovoid  cap  that 
extends  from  the  ridge-like  (upper)  free 
border  about  one-fourth  of  the  distance  to 
the  pectinate  base,  whose  full  length  is  more 
than  four  times  its  extreme  width. 

Bl.\ck  Hounbill.  (?)  Spagolobuti  adratus 
An  ophthalmoscopic  view  of  the  ocular 
fundus  of  this  species  is  pictured  as  Plate 
XLIII,  page  163  of  this  work.  The  painting 
is  of  the  right  eye  by  the  direct  method. 
The  shimmering  reflections  from  the  trans- 
lucent retinal  elements  of  the  fundus  make 
an  accurate  ophthalmoscopic  view  some- 
what difl^cult.  The  principal  color  of  the 
eyeground  is  dull  gray,  interspersed  for  some 
distance  about  the  optic  nerve-entrance 
with  a  mass  of  fine,  opaque  fibres  that  extend 
about  a  disc-length  over  the  fundus.  Beyond 
the  fibres  are  several  dull-colored,  choroidal 
capillaries  that  cross  the  fundal  field  in  a 
vertical  direction.  Near  the  macular  region 
the  fundus  is  illuminated  by  a  brilhant 
gray  iridescence. 

The  optic  disc  is  a  long,  white  oval,  that 
extends  downward  and  a  little  inward  towards 
the  inner  or  beak  side  of  the  head. 

The  pecten  is  very  large,  the  lower  seg- 
ment being  carried  so  far  forward  behind 
the  iris  that  it  is  difficult  to  inspect  it  with 
the  ophthalmoscope.  Instead  of  the  usual 
fringe  of  pigment  the  pecten  presents  serrated 
margins. 

The  macular  region  is  quite  circular  and 
is  red-brown  in  color.     An   inner  circle  is 


dead  white,  while  the  foveola  is  represented 
by  a  dark-red,  central  spot.  There  are  two 
bright  rings  around  the  macula  of  an  irides- 
cent, blue-green  color,  the  fundus  between 
the  two  circlets  being  a  light,  luminous  gray. 

EriiOPE.t.v  NujiiTJAR.  CaprimiHijas  euro- 
peus.  The  fundus  picture  (left  eye,  erect  image) 
of  this  bird  is  furnished  by  Plate  XLIV, 
page  163. 

The  eyeground  appears  orange-red,  every- 
where stijjpled  with  small,  red  and  brown 
patches  of  irregular  shape.  Scattered  about 
are  several  pigmented  areas,  such  as  one 
sees  in  the  eyes  of  human  .subjects  with 
disseminated  choroiditis.  This  condition, 
somewhat  modified,  is  seen  in  many  owls 
long  confined  in  zoological  gardens  or  aviaries, 
and  it  seems  to  be  confined  to  Night  Birds, 
and  to  be  one  of  the  results  of  confinement 
and  domestication.  In  many  respects,  also, 
the  eye  of  the  Nightjar  resembles  that  of  the 
Strigifornus  except  that  Caprimulgus  has 
fewer  choroidal  vessels  in  the  lower  half  of  the 
fundus.  These  arc  faintly  outlined,  but  they 
give  to  that  part  of  the  eyeground  a  deeiwr 
red  than  the  remainder  of  the  background. 

The  optic  papilla  is  short  and  broad. 
The  antero-posterior  view  with  the  mirror 
shows  it  as  a  dull,  grayish-white  body  large- 
ly covered  with  brown  pigment  dots.  Its 
margins,  where  it  is  not  obscured  by  the  mass 
of  the  pecten,  is  much  lighter  in  color.  Radi- 
ating from  the  sides  of  the  disc,  and  extend- 
ing for  a  short  distance  on  either  side,  are 
a  few  white  opaque  nerve  fibres,  which  are 
light  gray  and  become  less  distinct  on  the 
outer  side  of  the  papilla. 

Anna  Hummingbird.  Calyptc  annw. 
(Figs.  101  and  135;  macroscopic  view.)  The 
ocular  background  of  this  sjjeeies  shows  two 
plainly  marked  macular  regions,  the  nasal 
fovea  being,  as  usual,  the  better  defined. 
This  area  nasalis  is  seen  as  a  black  spot 
entirely  surrounded  (except  at  the  lower 
fourth  of  its  circumference)  by  a  halo  of 
dark  pigment  grains.  Outside  of  this  is  an 
untinted  zone  that,  in  its  turn,  is  encircled 
by  a  nebulous  ring  broader  below  than 
above.  The  tunics  of  the  eyeball  are  cut  to 
show  the  temporal  site  of  the  second  macular 


THE  FUNDUS  APPEARANCES  IN  VARIOUS  ORDERS  OP  BIRDS         101 


ri'Kion.  Fi(,'iire  135  furnishes  an  ciilarncd 
piclure  of  this  area,  whicli  is  a  (liipliratc  of 
the  area  ua.iali.t  except  that  the  fovea  is 
sliallower  anil  not  so  bhick,  wliile  the  pij^nien- 
tation  of  the  surrounding  ring  is  less  marked. 
The  pedeii  has  Hi  convohitions — IC  on 
each  side — united  to  a  long,  narrow  sinuous 
crest.  The  fold  that  constitutes  the  front  of 
the  free  border  becomes  broader  and  rounded 
as  it  gradually  slopes  from  the  crest  to  the 
superior  end  of  the  optic  disc.  Uncertain 
glimpses  are  gained  of  the  papilLiry  borders 
through  a  few  spaces  between  the  more  cen- 
tral pect'.nale  folds;  otherwise  the  surface  of 
the  optic  entrance  is  entirely  obscured. 

Cuculiformes 

Yellow-billed  Cickoo.  Cocn/ziis  ameri- 
catius.    (Figs.  lOi  and  130;  nuicroscopic  view.) 

The  single  macular  region  is  of  immense 
size — considerably  larger  than  the  untinted 
area  on  the  nasal  side  of  the  pectin,  and 
two-thirds  as  wide  as  the  optic  entrance  is 
long.  A  nebulous  zone  of  pigment  <lots 
encloses  this  large  .sensitive  area,  the  dots 
being  drawn  as  distributed  everywhere  ex- 
cept at  the  upper  fourth  of  the  zone,  where 
they  are  comparatively  few.  Tin-  foira  oc- 
cupies the  exact  center  of  the  circle  and 
shows  as  a  dark  pigiuent  spot  with  its  upper 
two-thirds  covered  with  black  granules 
closely  spread  above  it  fan-wise. 

The  peclen  has  about  24  heavy,  compact 
convolutions  that  almost  completely  cover 
the  optic  entrance.  They  are  joined  at  the 
irregidar  free  border  above  by  a  translucent, 
cigar-shaped  band  of  tissue  that  extends 
the  whole  length  of  the  crest. 

The  anterior  and  pointed  terminal  of  the 
papilla  approaches  to  within  less  than  a 
disc  width  of  the  temporal  boundary  of  the 
macular  region. 

Ei'HOPEAN  Cuckoo.  Cucuhis  canorus. 
The  ocular  fundus  of  this  bird,  as  .seen  in 
living  specimens  by  the  aid  of  the  ophthal- 
nioscoj)e,  is  depicted  on  Plate  XLV,  page 
105.  The  picture  is  drawn  of  the  left  eye; 
erect  image. 

The  coloration  of  the  cycgronnd  is  gr.ay 
with  a  suggestion  of  fawn,  everywhere  show- 


ing minute,  grayish-white  dots.  Towards 
the  lower  quadrants  of  the  fundus  and  in 
particular  at  the  extremity  of  the  pecten  the 
background  is  suffused  with  a  duii  pink. 
Near  the  optic  nerve  on  either  side  are 
several,  plainly  visible,  orange-red  choroidal 
vessels. 

The  macula  is  seen  above  the  disc,  towards 
the  nasal  side.  This  area,  slightly  red  in 
tone,  appears  depressed  below  the  fundal 
plane,  although  no  definite  fovea  is  visible 
with  the  mirror. 

The  papilla  is  almost  completely  covered 
by  the  pecten,  so  that  only  the  outlines  of 
the  former  can  be  seen  by  tlu'  antero-pos- 
terior  inspection  of  the  ophthalmoscope. 
\Yhere  the  papillary  margin  is  visible  it 
shows  extremely  white. 

The  pecten  also  extends  far  above  as  well  as 
below  the  disc  terminals  and  projects  deeply 
into  the  vitreous  chamber.  It  appears  by 
the  mirror  to  be  a  chocolate-brown  in  color. 
Opaque  nerve-fibre  radiations  are  seen  to  orig- 
inate at  the  disc  margins,  whence  they  cross 
the  background  and  finally  disappear  from 
view  at  or  near  the  periphery  of  the  fielil. 

Piciformes 

SrLPiitR-BnEA.STED  ToucAX.  Rhamphas- 
tu.t  lamatus.  As  shown  in  Plate  XLVT,  page 
105,  this  bird  has  a  dull-gray  eyeground  (when 
it  is  viewed  ophthalmoscopically)  rather  regu- 
larly spotted  with  whitish-gray  dots. 

The  optic  papilla  is  apparently  composed 
of  short,  coarse,  white  fibres  which  form  a 
sort  of  fringe  all  round  its  margins.  Along 
each  of  its  sides  and  parallel  to  its  long  diam- 
eter a  few  orange-red,  choroidal  vessels  are 
seen.  Radiating  from  the  papillary  circum- 
ference arc  numerous  opatjue  nerve  fibres 
that  extend  to  the  fundal  periphery  across  the 
eyeground  on  all  .sides. 

The  pecten  is  almost  black-brown  in  color 
and  in  shape  resembles  the  same  organ  in  the 
Ilornbills  and  the  Kingfishers,  especially  in 
the  former. 

Above  the  end  of  the  optic  nerve  entrance 
and  about  half  its  length  to  the  nasal  side  are 
three  dark-brown  spots,  clustered  together 
and  surrounded  by  a  small  gray  reflex.    This 


102 


THE  FUNDUS  OCULI  OF  BIRDS 


area  is  probably  the  macular  region;  at  least 
it  corresijoiids  to  its  usual  locality  in  other 
orders  and  presents  the  characters  one  might 
»xiM>ct,  knowing  the  habits  of  the  animal. 

Ked-siiafted  Flicker.  Colaptcs  mexican- 
us.  (Figs.  104  and  137;  macroscopic  view). 
The  ocular  fundus  of  this  species  presents  a 
single  fovea  (or  what  in  Man  is  called  the 
oteola)  that  seems  larger  than  usual;  at  any 
rate  the  central  black  spot  is  more  pronounced 
than  in  most  Birds.  It  has  no  well-defined 
macular  ring  but  appears  to  have  a  place  in 
the  uniformly  dotted  retina  al)out  half  a  disc 
length  above  and  slightly  to  the  nasal  side  of 
tiie  anterior  optic  terminal. 

The  peden  has  seventeen  double  toils  (34 
single  convolutions)  on  either  side  of  a  promi- 
nent and  rather  deep  keel  or  ridge  that  unites 
them  above.  Of  these  coils  two  stand  at 
right  angles  to  the  keel,  two  are  slightly  curled 
on  themselves  and  present  a  concavity 
towards  the  posterior  free  border,  while  the 
remainder  look  in  the  opposite  direction  with 
varying  degrees  of  concavity. 

Red-headed  Woodpecker.  Melanerpea 
erythrocephalus.  (Figs.  103  and  138;  macro- 
csopic  view).  The  general  appearance  of 
ihis  fundun  much  resembles  that  of  the  Red- 
shafted  Fhcker.  It  is  true  that  here  the 
macular  field  is  defined  by  a  boundary  of  faint 
printed  dots,  but  these  are  hardly  distin- 
guishable, except  at  the  infero-nasal  cjuad- 
rant,  from  the  pigment  of  the  neighboring 
retina.  In  the  center  of  the  sensitive  area 
is  a  single  black  spot  surrounded  by  a  cloud 
of  dark  granules  that  are  wanting  lielow,  in- 
tended to  depict  Xhc  fovea. 

The  pecten  has  34  single  convolutions.  Its 
structure  also  closely  resembles  that  of  the 
Flicker  just  described,  but  the  former  is 
larger,  the  folds  are  heavier,  and  the  uniting 
keel  is  wider  and  deeper. 

(iiL.\  Woodpecker.  Centurus  uropygialis. 
An  ophthalmoscopic  view  of  the  fundus  oculi 
of  this  bird,  as  shown  in  Plate  XL VII,  page 
167,  shows  it  to  be  dull-gray  tinted  with 
yellow,  and  nearly  uniformly  charged  with 
minute,  gray  dots. 

At  the  superior  termination  of  the  optic 
disc  (on  the  nasal  side)  is  a  small  gray  depres- 


sion, partly  surrounding  a  central,  well- 
marked  and  glistening  white  dot.  Within 
this  area  are,  also,  several  gohlcn  yellow  dots, 
which  can  be  seen  only  when  the  reflected 
light  of  the  ophthalmoscopic  mirror  falls 
obliquely  upon  them.  Owing  to  the  limited 
number  of  this  species  that  Head  and  the 
writer  were  able  to  examine  it  was  impossible 
to  say  whether  the  punctate  deposits  last 
mentioned  are  nornud  or  pathological.  Fur- 
ther ii.vestigation  of  additional  specimens, 
both  ophthalmoscopically  and  microscopically, 
will  be  necessary  to  decide  the  question. 

The  outlines  of  the  optic  nerve  entrance 
are  well  defined,  and  the  central  area  of  the 
papilla  at  its  union  with  the  pecten  is  dull 
orange  stippled  with  dark  brown  pigment, 
like  pepper  grains.  The  papilla  is  fringed 
with  coarse  white  fib-is.  A  large  nunil)er 
of  translucent  nerve  fibres  radiate  from  the 
edge  of  the  optic  disc  on  all  sides;  they  be- 
come fainter  and  fainter  as  they  approach 
the  fundal  periphery  and  finally  disappear. 

The  pecten,  of  the  usual  chocolate  brown 
color,  reveals  several  corkscrew  convolutions. 
It  comes  well  forward  towards  the  lens,  and 
presents  a  massive,  club-shaped  appearance. 
In  most  respects  this  fundus  picture  re- 
sembles the  eyeground  of  the  Greater  Spotted 
Woodpecker. 

Great  Spotted  Woodpecker.  Dryobates 
vet  Dendrocopus  major.  The  fundus  picture 
of  this  species  is  seen  as  Plate  XLVIII,  page 
167.  The  color  of  the  eyeground  is  a  uni- 
formly dull  but  definite  gray,  interspersed 
with  a  large  number  of  small,  gray  dots.  Be- 
low the  optic  disc  and  pecten  are  a  few  faint, 
orange-red  choroidal  vessels. 

The  optic  disc  is  apparently  built  of  a  mass 
of  brilliant,  white,  opaque  fibres,  very  short 
and  thick.  In  the  form  of  radiations  from 
the  margins  of  the  papilla  towards  the  fundal 
periphery  run  many  gray,  opaque  nerve 
fibres,  that  appear  to  occupy  a  plane  lower 
than  the  white  elements  of  the  disc. 

The  pecten  has  three  corkscrew  convolutions 
on  the  disc,  while  its  lower  part  forms  a  club- 
shaped  mass  of  a  deep  chocolate-brown  color 
that  appears  to  come  well  forward  towards 
the  lens. 


THE  FUNDUS  APPEARANCES  IN  VARIOUS  ORDERS  OF  BIRDS         103 


Fig.  139.     Western  Mockingbird  (Mimus  polyglottoa  Uucopterm)  X  U. 
Macroscopic  Appearances  of  the  Fundus  Oculi  in  the  Preserved  Eyes  of  Birds. 


lot 


THE  FUNDUS  OCULI  OF  BIRDS 


TlitTc  sc'cins  to  he  only  one  xcusitive  central 
etna.  This  single  iniiciila  is,  as  iisunl,  on  the 
nasal  sidf  of  the  jH'cten  and  has  the  apiM-ar- 
aiiof  of  a  lirillii.nt,  whit<',  round  dot,  Ihi-  fun- 
dus surrounding  it  Ix-iiig  a  little  darker  than 
the  general  color  of  the  eyegrouiid.  The  sur- 
rounding gray  area  makes  the  white  fovea 
stand  well  forward,  almost  as  if  it  were  actu- 
ally situated  in  the  vitreous.  N'o  reflex  ring 
can  he  se(>n  around  it. 

Passeriformes.    .-1.    Mcsomyodi 

Derby  Tyu.vxt.  Pilangus  derhianu.i. 
The  fundus  view  of  this  species,  shown  by 
Plate  XLIX,  page  169,  represents  ophthal- 
moscopic examinations  of  thrif  siH'cimens. 
The  six  eyes  of  the  three  birds  presented  ])rc- 
cisely  the  same  ophthalmoscopic  appearances. 

The  cyegroiini!  is  hliie-gray,  everywhere 
sprinkled  with  minute,  gray  dots.  These 
dots  are  .so  do.sely  packed  in  the  upi)er  half 
of  the  fundus  that  they  give  it  a  distinct 
silvery  appt-arance.  Running  at  right  angles 
to  either  side  of  the  optic  papilla  are  numerous 
dull-white  opaque  nerve  fibres.  These  arc 
near  together  and  extend  well  across  the  eye- 
ground. 

.\t  right  angles  to  the  optic  disc  towards 
the  nasal  side  and  a  little  above  its  superior 
end  is  a  dense,  pale-blue,  punctate  mass  that 
appears  to  surround  the  fovea.  A  light-blue 
reflex  ring  also  encircles  this  area. 

The  optic  nerre-entrance  is  long,  narrow  and 
white.  Its  centre  is  stippled  with  a  few- 
brown  pigment  dots,  and  it  is  bordered  all 
around  with  symmetrically  placed  black  pig- 
ment granules.  This  t)igmented  margin 
varies  a  little  in  indi\ ,  .iials.  The  pi'cten, 
long  and  narrow,  extends  well  behind  the 
edge  of  the  pupil  so  that  a  portion  of  it  can- 
not be  seen  Ihrougli  the  mirror.  The  upi)er 
part  is  serrated  but  the  lower  half  is  more  of 
the  corkscrew  type.  The  color  is  the  usual 
deep,  dull  brown. 

Passeriformes.    B.  Acryomodi 

EuHOPEA.N  Chimney  Swallow.     Ilinmdo 

rustica.     The  ophthalmoscopic  appearanci's  in 

this  sp'-'-ies  are  shown  on  Plate  L,  page  l69, 

and  dep.^t  the  erect  image  of  the  right  fundus. 


The  general  color  of  the  eyeground  is  warm 
gray,  tinted  slightly  with  yellow  or  bulF,  and 
covered  with  minute,  dull,  yellowish  dots. 
S<'veral  pale  orange  (choroidal)  blood-vessels 
are  seen  near  the  up|H'r  extremity  of  the  optie 
nerve-entrance. 

There  are  visible  two  macular  rrgion.i.  one 
on  each  side  of  and  above  the  upiwr  end  of 
the  disc.  They  show  as  small  brown  areas 
or  dots  in  the  eyeground.  Surrounding  the 
temporal  macula  is  a  slight  reflex,  apparently 
compr  "d  of  minute,  bright  gray  dots.  Th(> 
macuht  on  the  nasal  side  is  quite  devoid  of 
this  reflex-ring. 

The  optic  papilla,  long  and  narrow,  tapers 
at  its  uppi-r  end.  On  either  side  of  the  disk, 
and  at  right  angles  to  it  are  a  few,  fine,  dull- 
gray  opaque  nerve-fibres. 

The  pccten  is  quite  narrow  at  its  junction 
with  the  optic  nerve,  but  it  gradually  beconu-s 
wider  and  more  ma.ssive  as  it  approaches  the 
lens.  It  is  of  the  usual  chocolate-brown  color, 
and  is  convoluted. 

Westebn  Mockixgbihd.  Mimun  pohj- 
glottos  leiicopterus.  (Figs.  105  and  139;  mac- 
roscopic view).  In  this  fundus  are  s  n  two 
sensitive  areas.  The  area  nanalia,  lying  above 
and  anterior  to  the  superior  end  of  the  optic 
entrance  about  half  th','  length  of  the  papilla, 
is  seen  as  a  black  spot  capped  on  its  temporal 
aspect  by  a  semi-circle  of  large  pigment 
grains.  The  whole  macular  region  is  not 
only  bordered  by  pigment  but  the  intervening 
zone  is,  in  the  nasal  three-fourths,  also 
•sprinkled  with  minute  granules.  The  area 
temporalis  is  placed  almost  directly  posterior 
to  but  much  farther  from  the  upiier  end  of 
the  disc  than  the  na'  '  fovea.  It  is  evidently 
shallower,  is  less  plainly  outlined  and  the 
foveola  is  not  as  large.  [The  black  line  run- 
ning along  the  left  side  of  the  large  figure 
indicates  that  a  segment  of  the  globe  has  been 
removed  —  to  show  the  temporal  macula.] 

The  very  long,  narrow  pecten  has  52  single, 
compact  convolutions  thai  everywhere  hide 
the  optic  entrance.  A  moderately  deep  and 
wide  keel  unites  the  pectinate  folds  along  the 
upper  free  border  of  the  pecten  almost  to  its 
junction  with  the  superior,  pointed  end  of 
the  disc. 


THE  FUNDUS  APPEARANCES  IN   VARIOUS  ORDERS  OF   BIRDS         10« 


I 


Fig.   141.     California  Shrike  (ianiM*  iudoricianm  gam6«/i)  Xli. 
Macroscopic  Appearances  of  the  Fundus  Oculi  in  the  Preserved  Eyes  of  Birds. 


106 


THE  FUNDUS  OCULI  OF  BIRDS 


Amekican  MocKiN(iuiRD.  ilimun  pnly- 
(jlolton.  The  ophfhulinoncojx*  showM  the  pn>- 
valfiif  colorution  of  the  fundus  in  this  .sfx-fies 
to  Ix-  a  clear,  blue-gruy.  Thickly  scpttercd 
over  tlie  background  lire  irregularly  sha|)ed, 
whitisli-gruy  dots  or  granules  that  in  the 
upper  s«'ctors  of  the  fie!d  give  the  fundus  an 
unusually   bright   gray  appearance. 

Xear  the  upper  extremity  of  the  optic 
papilla  and  towards  the  nasal  side  is  the 
mnciild.  Tli'  area  is  darker  blue  than  its 
surroundings,  while  its  centre  (the  fovea)  is 
marked  by  a  bright  white  dot  which,  again,  is 
enclosed  in  a  green  reHex.  This  gn-enish 
reflex-ring  has  a  striated  appearance,  the 
strii>>  being  (|uite  translucent  and  convergent 
towa-ds  the/orfa  centralin. 

The  opiic  difc  is  long  and  narrow;  the  visible 
portion  is  brilliant  white  and  its  margins  are 
traceable  on  either  side  the  whole  length  of 
the  pecfen.  Radiating  f'.nm  the  boundary 
of  the  ner.eliead  are  many  long,  opaque 
nerve  fibres  that  extend  over  the  cyeground 
to  its  periphery. 

The  perten  is,  as  usual,  of  a  chocolate-brown 
color;  it  is  long,  .■somewhat  club-shaped  and 
extends  well  behind  the  margin  of  the  iris, 
so  that  its  outlines  are  not  entirely  visib'*?  by 
the  mirror  through  the  undilated  or  only 
partially  dilated  pupil. 

The  fundus  of  the  Cuban  Mocking  Bird 
(J/,  orpheus)  is  similar  in  every  resjiect  to 
that  of  Mimu9  polyglotios. 

Bluebird.  Sialia  siaHs.  This  was  one 
of  the  earliest  species  examined  ophthalmo- 
seopically  by  the  writer,  and  he  was  so  struck 
by  the  wonderful  blue  coloration  of  the  ocular 
background  that  the  question  arose  in  his 
mind  as  to  whether  there  might  not  be  some 
connection  between  plumage  tints  and  fundus 
colorin;-,.  That  query  was  soon  answered  in 
the  negative  but  the  beautiful  blue  shades 
in  the  eyegiound  of  Sicdis  are  still  to  be 
admired. 

.\s  seen  in  Plate  LI,  the  ophthalmoscope 
shows  that  the  general  blue-gray  coloring  of 
the  eyeground  is  modified  by  numerous,  pin- 
point dots.  The  punctate  deposits  near  the 
I>eriphery  assume  a  more  or  less  dull-golden 
or  orange  tint,  a  condition  also  noticed  just 


below  the  pcctcn.  The  elongated,  ovoid 
optic  disc  is  white  (quite  woolly  a  I  its  margins) 
and  covcr-d  almost  iiitirely  by  the  convo- 
lutect  pecton,  which  is  very  large  when  com- 
pared with  the  size  of  the  eye.  A  portion  of 
the  unusually  extensive  jx-cten  cannot  \te 
si>cn  through  the  small  pupil.  It  is  of  the 
usual  dull-brown  color,  and  has  "frilled" 
borders.  On  the  inner  ■  r  nasal  side  and  near 
the  lower  part  of  the  optic  disc  is  an  orange- 
red  area,  containing  chieP.y  choroidal  vessels 
with  black  pigment  grains  betw»>en  them. 
This  red  area  extends  a  little  to  the  temporal 
side  of  the  disc,  subsequently  merging  into 
the  dull  orange  color  below.  On  either  side 
of  the  disc  and  radiating  from  it,  are  numer- 
ous filiform  nerve  fibres  which  cross  the  back- 
ground almost  to  its  periphery.  In  an  area 
a  disc-length  to  the  nasal  side  of  the  papilla, 
the  white  dots  of  the  fundus  are  fainter  and 
much  closer  together  than  elsewhere;  and  in 
this  region,  also,  there  is  a  reflex  plainly 
marked.  Here,  if  in  any  part  of  the  fundus, 
is  the  fovea  or  macula,  but  it  is  not  sufficiently 
well  defiled  to  he  certain  of  it. 

Figures  106  and  !  10  demonstrate  quite  con- 
clusively that  in  the  fundus  of  Sialia  sialia 
there  are  two  macular  areas,  symmetrically 
placed  above  and  on  either  side  of  the  pointed 
eiid  of  the  papilla.  The  area  nasalis  is  removed 
about  half  a  disc  length;  the/or«a  temporalis  is 
somewhat  more  distant  from  the  same  point. 
The  nasal  macular  region  is  liirger  and  more 
plainly  marked;  it  is  surrounded  by  u  dotted 
ring,  incomplete  above;  the  corresponding 
foveola  is  represented  by  a  black  spot  crowned 
by  pigment  grains.  More  than  half  the  inter- 
vening zone  is  lightly  strewn  with  minute, 
dark  granules. 

The  heavily-built  pecten  is  composed  of  19 
thick,  rounded,  double  folds  —  or  38  con- 
volutions. A  comparatively  massive,  paddle- 
•shaped  crest  surmounts  these  and  extends 
along  the  whole  of  the  upper  free  border. 
The  major  axis  of  the  papilla  makes  with  a 
line  joining  the  two  foveolee  an  infulapapillary 
angle  of  about  70°.  There  is  nothing  to  be  seen 
of  the  nerve  head  from  above. 

Wheateak.  Saxicola  <Bn  .une.  The  color 
reproduction  shown  in  Plate  LII,  page  171, 


THE  FUNDUS  APPEARANCES  IN  VARIOUS  ORDERS  OF   BIRDS 


107 


furnishi's  an  i-xart  virw  iif  the  nphllialmo- 
xropic  npix-iirniufs  ot'  the  fiinilus  iK'iiIi  of  tlii.t 
.s|)«'cii'-t.  It  is  of  (lie  left  cyr,  crt'cl  iliiaK<'. 
Th<-  K*'>><'>'i>l  fiiiiilal  coloratioii  is  paU-  ^rny, 
with  a  (li'iisc  mass  of  uriiyisli  whiti-  tlols 
|KTnifatiii^'   the  I'litin-  'lackground. 

Sli){litly  aliiivc  tlic  upiMT  tcrniiriation  uf  tho 
optic  mTVc,  anil  towards  the  nasal  sidt"  of  the 
|M'ftfn,  is  a  wi'll-dcfiiicd,  round,  white  an-a, 
(tlif  iiiiiciilii  i'nd  f<vei!)  much  larger  tlian  the 
small  spots  tiiat  cover  the  whole  of  the  sur- 
rounding, duller  eyeground.  This  white  area 
is  inclosed  Ity  a  brilliant ,  bluish-green  circle, 
which  appears  more  prominent  an<l  iridescent 
in  nature  than  is  depicted  in  the  drawing. 

Little  can  he  seen  of  the  opiir  papilla  he- 
cause  it  is  almost  entirely  obscured  by  the 
IK'cteii.  However,  it  is  long  and  nn'row,  with 
an  irregtdar  outline. 

On  the  nasal  side  of  ti.e  nerve-head  are  a 
few  short,  orange-red,  choroidal  blood-vessels 
with  a  few  dots  of  pigment,  like  jH-pper  grains, 
sprinkled  belweep  them.  Extending  from 
both  margins  of  the  optic  disc  across  the 
fundus  to  the  periphery,  arc  numerous  fine, 
opa(iue  nerve  fibr»'s,  the  upper  ones  (on  the 
nasal  side),  terminating  at  the  macular  area. 

Till'  pecten,  red-brown  in  color,  long  and 
narrow,  appears  to  be  twisted  on  itself  like  a 
rope  or  a  corkscrew.  Its  inferior  end  extends 
lieyond  that  part  of  the  eyeground  shown  in 
the  picture,  but  it  probably  comes  well  for- 
ward towards  the  posterior  surface  of  the 
lens. 

English  Nightingale.  Aedon  megaryn- 
cha.  The  ophthalmoscopic  appearances  of 
this  species  is  almost  identical  with  those  of 
the  Wheatear  (see  Plate  LII,  page  171),  ex- 
cept that  in  Saxicola  the  macular  region  is 
not  so  well  defined. 

Califounia  Shrike.  Lanius  Indoricianus 
(jambeli.  (Figs.  107  and  141;  macroscopic 
view). 

There  are  hro  macular  region'  in  the  fundus 
of  this  bird,  similar  in  every  detail  to  the  same 
area;  in  the  Bluebird. 

The  optic  papilla  is,  however,  longer  and 
soniewliat  narrower  in  Lanius,  and  the  more 
extensive  pecten  exhibits  folds  joined  along 
its  free  borde-  by  a  rounded  crest  that  from 


above  takes  on  the  shape  of  n  carrot.  The 
major  axis  of  the  Ioi;<i  ovoid  <lisc  projected 
until  it  meets  a  line  crossing  the  floor  of  the 
(■oncave  fimdus  .in<l  joiii  :g  the  two  fovcohe 
would  subtend  an  (infulanapillary)  angle  of 
about  110°. 

Passerifo.'mes.    li    Alaudidae 

EfnoPEAxTiTLAiiK.  Atiihus  proknnK.  A 
healthy  adult  male  individual  of  this  .s|M>cies, 
about  three  months  in  captivity,  obtained 
from  u  dcal'T,  was  examinei,  by  the  writer  in 
the  laboratory  of  St.  Luke's  hos|iital.  The 
pupils  were  unaffected  by  one  drop  of  a  1% 
sol.  of  atropia  instilled  48  hours  previously. 
The  bird  was  strongly  hyperopic  and  very 
slightly  (about  0.33  D.)  astignuitic,  the  skia- 
scopi"  showing  3.30  D.  of  HAS  in  each  e,\  •. 

The  ophthalmoscopic  examination  revealed 
no  opacities  in  the  ocular  media. 

The  pecten  is  of  the  usual  black-brown 
color;  it  is  large  and  spiral,  filling  the  whole 
pupillary  area  when  examined  with  the  mir- 
ror, and  almost  entirely  obscures  the  outline 
of  the  optic  papilla  from  whicn  it  springs. 

The  background  is  of  a  fine,  p<'pper-and- 
salt  character  with  a  very  few  opaque  nerve 
fibres  radiating  from  t'lc  disk.  Scattered 
over  .!ie  field  are  man;  bne  sparkling  points 
like  minute  grains  of  cholesterine.  These 
are  also  to  be  found  in  the  macular  region, 
which  is  definitely  outlined  directly  in  the 
axis  of  vision  and  covers  a  space  about  J  3  of 
a  disc-len>;th.  The  mirror  does  not  show  a 
second  area  of  acute  vision. 

Passerifonnes.    B.  Fringillida 

Bkitish  Linnet.  Linoia  cannabina.  The 
indirect  ophthalmoscopic  examination  of  an 
imported  individual,  in  captivity  a  year  or 
less,  shows  a  jwctep  'hat  obscures  a  view  of 
the  fundus  details,  but  the  prevailing  color 
of  the  eyeground  iy  readily  seen  to  be  ,1  beauti- 
ful, light,  gray-Mue  beset  with  whitish  dots. 

British  Gcldfixch.  Cardueli.i  elegans. 
The  fundus  01  this  bird  as  seen  by  the  indirect 
method  —  it  was  extremely  difficult  and  un- 
satisfactory to  make  an  ophthalmoscopic 
examination  by  the  erect  image  —  showed  an 
eyeground  that  resembles  that  of  the  Linnet 


108 


THE   Fl'N'DUS  OTl'LI  OF  BIRDS 


Fig.  Hi.     Atiieriuin  Oow  (Conua  amerii-aniu)  Xh. 
MwToscopic  AiiiK'ftrBncfs  of  the  Fundus  Oculi  in  Ihc  PrfStTved  Eyes  of  Birds. 


in    J>eing    uniformly    lij,'ht    liluc-griiy.     Tlic 
IX'cten  obscun-il  most  of  thi-  field. 

BniTi.>iii  SmKiN.  Chn/somitris  spiiiun. 
One  of  thi.s  species,  obtained  from  n  dealer 
and  said  to  have  l)een  captive  for  si.\  months, 
was  examined  by  the  indirect  method  throuKli 
the  small  and  undilaled  pupil.  There  was  a 
relatively  large  pccten  which  made  it  impos- 
sible to  outline  '  he  optic  nerve-entrance  clear- 
ly or  to  (letern  ine  the  fundus  details.  How- 
ever, the  prevailing  color  of  the  eyeground 
was  light  gray-buie,  more  or  less  regularly 
besprinkled  with  minute,  yellow-white  dots. 

HorsE  Si'.\nnow.  Panser  domesticiis. 
The  ocular  fundus  of  ihis  typical  sj;'jcies  is 
pictured  as  Plate  LHl,  page  173  the  result 
of  the  ophthalmoscoj)ie  examination  of  numer- 
ous specimens.  The  dominant  coloration  of 
the  eyeground  is  pale-gray  covered  with  very 
fine  white  dots,  closely  packed  together  at  the 
mae!ilar  area.  They  form  a  lighte-  Kone  a 
litils  above  the  upper  extremity  of  the  pecten 


and  towards  the  nasal  side  of  the  disr.  Frnm 
the  circumference  of  the  optic  disc  a  large 
numlK-r  of  rather  long,  opa<|ue  nerve  fibres 
run  in  radial  fashion  towards  the  periphery 
of  the  fundus. 

The  papilla  appt>ars,  when  visible,  to  be 
composed  of  irregularly  shaped,  brilliant, 
white  bundles;  it  can  barely  be  outlined  with 
the  mirror  except  at  the  upper  (and  narrow) 
end  of  the  p<'cten. 

The  pecten  has  a  de<'p  red-brown  color,  and 
its  free  extremity  is  long,  narrow  and  of  the 
corkscrew  type.  The  lower  segment  of  the 
organ  extends  well  forward  towards  the  lens 
and,  being  large  and  massive,  completely 
covers  the  pupil  and  makes  it  impossible  to 
obtain  a  lateral  view. 

Vakiei)  BuNTiNO.  Cynnnspiza  versicolor. 
Plate  LIV,  page  173,  represents  the  ophthal- 
moscopic appearances  of  this  species.  The 
prevailing  color  of  the  eyeground  is  dull  gray 
shading  to  buflF.     It  is  covered  all  over  with 


TIIK   Fl  \nrs  ArPKAHANCES   IN   VAHIOIS  ORHKHS  OF   IIIIIDS 


ion 


«<r.v  ininiitc.  »:rii.vi<.|i-»liili-  ilnt^.  TlicfM-  dol* 
coiili'M'f  III  till'  tiKiciilii  »lnT«'  IIh'.v  form  ii  soft, 
nmml  nrrii  linrilcn-tl  liy  ii  li(,'lil  rcllcx.  Ti  .• 
Hiri^lr  rriHi'iihir  rrKioii  iinil  fiivni  iir<-  ><iliiiili'i| 
a  litlli'  iil>ii\<  the  u|)|H'r  t'lifl  of  tlir  (H'tl'ii  hihI 
tnwiinl'*  tlic  niiiiil  »i<U'  of  llif  opiic  !,■  rvc. 
The  i>irltn,  vtTV  liirjp'  mid  tim,«.sivc  for  Ihc 
»i/i'  of  tlir  ryr,  is  of  the  ii^iiiil  cliocolitlr- 
hrowii  I'olor;  it  is  niort'  or  less  ('IiiIi-s|i;i|m'i1, 
mill  I'xlcnils  Well  fiirwiiril  lowiinis  the  lens. 
At  liiiK-s  it  (|iiit<  (ills  the  iip'ii  of  Ihi'  |>iil)il,  so 
thill  I  lie  fiiiiiliis  is  ilillii  nil  |o  t-xpion-.  Tin- 
p«'«'tcn,  whose  outline  in  very  irrcKu!ar,  covers 
the  piipilla  entirely  so  that  it  iip{MNirs  to 
spriiiK  (lircclly  fniiii  the  retiiiii  without  show- 
ing the  while  disr  iiiarK'iri  found  priicticiilly  in 
all  birds.  I'Vorii  the  sides  of  the  iippnrent 
root  of  the  |H'eten  a  few,  whitisi.'.  opa<|Ue 
nerve  filin's  jtoss  the  field  of  vi<'w. 

Passerifotmes.     Ii.    Tanagridir 

Sc.Mii.KT  TwAiiKH.  Pirimgn  rrylhromrlan. 
The  dominant  coloration  of  the  eyejrround  \v 
this  sped'  —  readily  M-en  hy  aid  of  the  in- 
direct method — is  a  clear,  hriffht  gray- 
hrown,  .sprinkled  with  numerous,  glittering 
whitish-yellow  points. 

Law  Hiud  of  Pauadise.  I'nrolla  lairli. 
I'lale  LV,  page  17ii,  gives  an  ophthalmoscopic 
picture  of  the  fundus  of  the  left  eye,  erect 
image. 

The  cycijround  apfK-ars  yellowish  gray,  or 
khaki  color,  almost  uniformly  covered  with  a 
dense  mass  of  minute  white  dots,  thiut  are 
smaller  and  deu.ser  at  the  macular  region.  A 
few  <lull-red  choroidal  capillaries  an-  visible 
on  the  lower  part  of  the  fundus  near  the 
jwriplicry. 

The  oplir  nerve  head,  dull-white,  long  and 
narrow,  has  a  rounde<l  up|ier  end.  Its  entire 
central  area  apiiears  •■■.  if  it  wen-  a  mass  of 
fine,   I  Town   pigment  dots. 

The  perten  is  exceptionally  long,  rather 
narrow,  spirally  arranged  and  extends  beyond 
the  range  of  vision  through  the  undilated 
pupil.  It  i.s  similar  in  many  respects  to  the 
fundus  of  the  Common  Pigeon. 

To  the  nasal  side  and  a  little  above  the  end 
of  the  disc  is  the  macular  region,  which  .'ppears 
us  a  dull-brown,  crater-like  depression  bound- 


ed by  a  white  mass  of  (reflex)  strialions. 
Opaipie  nerve  fibres  radiate  from  both  siiles 
of  the  di-c  but  finally  disa|i|)ear  as  they 
approa<  Ii  the  boiiiiilaries  of  tlu'  fundus, 

Pasierlformes.    ( 'nrridir 

Ulik  Jav.  ('iinniM-itlii  erintaln.  The  fun- 
dus ap|M-arances  as  ri-vealed  by  the  oplilhid- 
mosco|M'  ill  the  left  eye  of  one  of  this  s|M-cic  > 
is  depi<led  as  I'liite  L>I,  page  17.V  The 
gi-neral  color  of  the  eyegroiind  is  a  slate-gray, 
with  an  added  pale-yellow  tint  in  the  lie  er 
half  of  th.-  eyegroiind.  The  entire  •'■•l-l  n 
Ix'spriiikled    with    irregularly    sha("  +- 

gray  dots,  giving  it  the  iip|H''         <  J| 

and  rather  coarse  surface,  es|H-<iall;  j« 

macular  area  win  re  the  dots  are  iin  -^ 

packed    in    the   shape   of   a    bright  rr,f 

patc'i. 

The  optir  nerre-head  is  quite  'vhii  ..f 

oblong  shiifx'.     Several  orange-ccl'x  o- 

roidal  capillaries  are  visible  i  i  ifn  i;ion, 
covered  with  minute,  brown,  piprc  dots, 
liki  black  iM'pjM-r  grains.  Sprint  I  iboiit 
each  side  >:'  the  optic  disc  is  n  large  i.ainiber  u( 
opaque  nerve  tiincs  that  cxtenif  across  fl' 
fundal  field. 

The  perten,  of  the  usual  cboei  U»to-t(ri.«ii 
color,  is  rather  irregular  in  shajx-      ;  it<  .«u|!' 
rior   extremity.     From    above   <i-  wnwani    >=- 
looks   lii.e   a    tarred    ship's   .  bec'-miBjE 

larger  as  it  approaches  its  .ii  wit,     t'n- 

papilla.     The   length   and   lit;    .iiess  o{      h; 
organ  ^compared  with  the  si/r  ,,f  the  eye  *r 
pupi!     make  it  diflicult  to  follow  its  out    >i-. 
throughout.     The   superior   end    apiX'iM 
come   well   into  the   vitreous  cavity   iin'i    l<, 
reach  the  lens. 

Stkllkii  Jay.  Cyanocitta  ulelleri.  (Fig 
111  and  10!);  macroscopic  view).  The  ocula; 
hack-ground  of  this  siM-cies  exhibits  a  moderale- 
.sized,  though  well-marked,  single,  circular 
macular  region.  'Dwforeola  is  shown  as  a  dark 
spot  crowned  by  minute  pigment  grains  thai 
mingle  with  a  similar  jiignient  ring  of  granules 
that  .serve  as  a  boundary  for  the  whole  region. 
There  is  a  small,  kidney-shaped  space  lc- 
tween  these  two  collections  of  dotted  pig- 
ment that  .seems  free  of  color.  The  centre  of 
the  fovea  is  slightly  above  and  about  half  a 


.(^^)><f»iii9C'uazm^  '.nejrtr, 


no 


TlIK  FUXDl'S  Ornj  OF  BIRDS 


Hiiw-lenKth  from  f  hr  anlrrinr  rtid  cif  the  nptic 
riilranir, 

Th)*  lonit  nml  wide  prrlrn  hait  A4  Kinglc  coii- 
vi)luti()ti!<,  and  in  Nhapr  n-M^nililrx  I  lie  nanw 
iirKiin  in  the  t  irikf,  rxrcpt  Ihiit  from  the 
<vnl<T  of  itit  cTTNt  ri»r»  a  iihort  spint-  cnxily 
Mfn  in  l)'>th  fiKurrii.  Thr  optic  papilla  i.n 
nlnioxt  ronipletely  hiildcn  by  the  niaiw  of  the 
niar!«upitim. 

Amkhican  Chow.  Ciirrut  anifriranuf. 
(Fi«."t.  lOH  and  144;  macroscjipic  view).  Thon- 
is  in  the  bark((round  of  thin  .s|>pcif.H  an  nn-a 
of  a<'Ul»'  visual  prrtvption  r«'pr«'!M'nle<!  Iiy  a 
retinal  bar  or  hand  at  wIiom'  middle  |M)int  in 
Mfn  a  w»-ll  dj'fineil/orf  a,  the  <Tnter  of  a  macu- 
lar region  formed  l>y  a  widening  of  the  hand 
itM'If.  The  hand  stwtelii  horizontally  acroits 
the  fundu's  and  ii  centrally  Icx-ated  >n  the 
field  of  view.  It  is  of  medium  width,  out- 
lined hy  a  uniformly  dotted  line  above,  but 
less  iiistinctly  Ih-Iow  hy  a  string  of  minute 
granules  that  more  or  less  tint  the  lower  half 
of  the  band  itself.  The  macular  region  is 
formed  liy  a  widening  of  the  sensitive  hand  to 
form  an  oval-shaped  region. 

The  superior  ei.d  of  the  papilla  is  one-half 
its  length  from  the  foveola. 

The  large  pecirn  (thnn'-fourths  the  length 
of  the  retinal  hand)  is  formed  of  about  61 
uniformly  compressed  convolutions  joined 
at  their  free  margins,  above,  by  a  shallow, 
dumb-l)ell-shaped  crest  that  slopes  gradually 
from  h«>hind  forwards. 

If  the  major  ixis  of  the  papilla  —  obscured 
by  the  pectiua  ■  mass  —  were  projected  to 
meet  the  temporal  end  of  the  retinal  bur  it 
would  describe  an  (infulapapillary)  angle  of 
about  60°. 

EinoPEAN  Cahhion  Crow.  Corrus 
corone.  The  writer  examined  in  the  Labora- 
tory of  St.  Luke's  Hospital,  Chicago,  an 
adult  male  of  this  species,  imported  from 
Germany.  He  ha<l  In'on  in  captivity  about 
a  year.  Boti  eyes  w,  re  healthy.  He  used 
his  nictitating  membrane  freely  on  the  ap- 
proach of  light  'o  the  eye.  The  pupils  varied 
in  diameter  fi  im  2  to  ;.50  mm.  A  single 
drop  of  1%  solution  of  atropine  sulptiate  info 
each  eye  produced  no  effect  on  the  ^ize  or 
movements  of  the  pupils  during  the  following 


4H  hours.  The  same  negative  rmult  waa  ob- 
tained hy  the  u<«e  of  a  one-fifth  per  cent  solu- 
tion of  hyimein  and  by  a  mixture  of  honiatro- 
pine  and  cocaine.  Skiascopy  in  the  dark 
rtMtni  showed,  iHith  liefore  and  after  the  use 
of  atropia,  a  hy|M>ropia  of  41). 

Hy  the  dir«H't  method  lh«'  l-irkgrouml 
ap[H>ars  to  Im>  almost  uniformly  dark  red- 
brown.  The  macular  rrgiim  is  set-n  with 
difficulty. 

The  oplic  difc  is  a  long,  while  oval  with 
the  pecten  a  very  black,  corkscrvw-like  organ, 
appar«>ntly  changing  plan*  and  shape  rapidly 
under  examination. 

Common  Uhitihii  IlLArKBiRD.  TurduK 
merulii.  The  ophthamo.scopic  picture  of  this 
sjM'cies  is  repro«Uice<l  as  Plate  LV'II,  page  177. 
It  shows  the  eyeground  as  seen  in  the  left  eye 
by  the  direct  methcMl.  The  general  tint  is  a 
slaty-gray  with  a  uniform  sprinkling  of  tiny, 
white  dots.  There  is  no  visible  macular 
region,  hut  tiie  whole  fundus  is  covered  and 
i;  :>loring  greatly  modified  by  minieroits, 
linear,  opaque  fibres  that  ari.se  from  the  di.sc 
margins  throughout  and  run  across  the  entire 
fundus  to  the  extn-me  periphery.  A  few 
faint,  yellow-red  choroidal  vessels  are  seen  on 
either  nAv  of  and  paritllel  to  the  moderately 
long  and  narrow  papilla.  The  upper  two- 
thirds  of  the  disc  is  aliout  half  covered  by  the 
club-shaped  pecten,  Vvhich  is  apparently  com- 
posed of  very  few  folds.  The  massive,  choco- 
late-colored, posterior  end  of  this  organ  en- 
tirely obscures  the  lower  third  of  the  nerve- 
head,  while  the  upi)er  half  of  the  former  has 
a  light  brown  niargiii  on  its  nasal  aspect,  and 
seems  to  be  only  in  part  attached  to  the  nerve- 
head  beneath  it. 

Raves.  Corvuscorax.  Thf  fundus  picture 
(right  eye)  shown  by  Plate  LVIII,  page  177, 
represents  the  (similar)  appearances  in  a 
number  of  specimens  examined  with  the 
ophthalmoscope  by  Mr.  Head  in  the  London 
Zoological  (iardens  and  hy  the  writer  in  the 
aviary  of  the  Bronx  Park,  New  York. 

The  eyeground  is  a  light  fawn  sprinkled 
with  dots  about  three  shades  darker  than  the 
ground  color.  Mixed  with  the  dark  dots 
are  numerous  white  ones,  seen  especially  when 
a  strong  light  is  thrown  upon  the  fundus. 


THE   FI'MUS   .\IM'f:.VI«,\\(  KS   IN    VAHIOI  S  OHDKHS  OF   HlllDS         III 

MmmiI    HiriT   iliM-hniiiltliH   from   ijir   iip|Nr         Ihr  lnwi-r  part  of  tin- fiiii,|i„.  ,u«NiiiliMl  «itli 


mil  of  thr  ilioc  on   Ihi'   iiiiirr  >ii<l.'  \n   a  «.ll         iitniiiilMrof  nraiitft-rid  ilols.nn- a  fi«  oni 


iirknl     liriKlit    n-lliA    of    a    unTni-li-l.l 


UK"'- 


liliK<'.     It    ii   irri'Kiilarly   oval   in   >lia|M'   aii>l         lallrr  In 
m-i'iiii*  to  Ik-  ('oiii|H>Hi'<t  of  a  iiiinilM'r  of  very 


ml    rlloroiilai     IiI<hh|-vi"<-.i-I'<,     ti'ViTnl    of    III) 


I  ill-  <liM'. 


iiiK  iliilriltiili'il  alonx  lillirr  liilc  of 


liiif  filircv,.     Ill  flic  (riittr  of  till-  r<  llix  is  lli. 


Tlir   /i.(7.»i.»   ill   all   llic    Ha\iii^   iA;iiiiiin<l 


«i./n//(i.  a  small,  ilark.  iralir-lik.'  .'.iirt'sMon,         win-  of  similnr  slia|)c  iiml  of  llir  iiMial  ihirk.- 


lirowM   ill  i-olor.     Till-  liiv  is  chalky   uhil 
mill  K>V('!*  one  till-  impression  that  il  is  nui 


|M>si-f|  of  many  opai|iii'  lurvi-  lilins  p.nknl         liny   approai  linl   llii-   Inis   »h«rr   II 
i'los«'|y    foK<' 


From    Ihr    (list     ma 


iirowti  nilor.     Tlicy  «i  ;.    vi-ry  lliiii  ami  nar- 
row  al   Ihr  ilisc  liiil  assiininl  a  i'liili-slia|M'  as 

irv    «i  r<' 


llicn-  ratliatf  ..  niinilH<r  of  (i 
fihrrs  that  cxti-nil  in  ross  I  hi-  cv 


rKiiis 
IK-  o|)li<'  iirrvi' 


I'Kroiiiii 


I.     Il 


clarkiT  in  color.  Tlic  |k'cIcii  comes  will 
forwaril  ami  ap|M'ars  at  limes  In  press  hk"'""'' 
the  |M>sicrior  capsule  of  the  lens. 


_1 


Chapter  X 
CLASSIFICATION  OF  THE  OCULAR  FUNDI  OF  BIRDS 


The  piirlicoldrcd  avian  l)a('knr()und,  as  sct'n 
liy  the  oplithalnioscopp,  although  of  groat 
variety,  may  he  (lividcd  into  two  major 
calt't^orios  and  racli  of  tlu'so  into  five  sub- 
divisions,  as  follows: 

A.  Tlie  iirasriilnr  fiiiKlKn,  in  wliich  thort- 
art-  no  visit)l<"  n  tinal  or  choroidal  blood- 
vessels. 

This  elass  resolves  itself  into  (a)  those 
avascular  eyeprounds  in  which  the  predomi- 
nant color  is  llfihl  (jraji  or  (jratj-hluc.  These 
fundi  are  comparatively  rare,  but  examples 
of  them  are  found  in  the  Varie<i  Bunting 
(Plate  LIV)  and  the  Iin-eaha  Rail  (Plato 
XIII). 

(fc)  Dark  lira;/,  drcp  grati-bhiv  or  slale- 
rolorcd  arasnihir  fundi  are  ((uitc  common. 
The  llarle(|uin  Quail  (Plato  VIIl),  Knplish 
Sparrow  (Plate  LUI),  Derby  Tyrant  (Plate 
XLIX).  IJrush  Turkey  (I'lale  VII),  Varroll's 
Curassow  (Plate  VI),  Sulphur-crested  Cocka- 
too (Plate  XIJ),  and  the  European  Bittern 
(Plate  XXI)  are  samples.  The  fundi  of  the 
(reeled  Coot  (Phile  XII)  and  of  the  Black 
lloriibili  (Plate  XMII)  bohmg  to  this  sub- 
division but  they  also  show  u  greenish  tinge. 
((■)  YcUnir.  oraiirjc  and  nrangc-rcd  bloodless 
fundi  belong  almost  ex(  lusively  to  N'iglil 
Birds,  or  to  thoM'  that  use  their  eyes  for 
both  diurnal  and  tioiturnal  visualizalioii. 
Such  fundi  are  seen  in  the  .\i)tcryx  (Plate 
IV),  Camiet  (Plate  XXIX).  and  tli.'  Black- 
fooled  Penguin  (Plate  XIN).  Tie  corrcs- 
piinding  elass  of  rascidar  fundi  is  a  inu<'h 
largir  one. 

((/)  Fundi  of  a  hnnrnish  or  ru.isil  roliir. 
slioirinfi  no  rascuhtr  sni)i>lt/.  are  ralher  com- 
mon. Examples  are  sei'n  in  the  .\ma/on 
C.oiden  Parrot  (Plate  XXXIX),  South  Amer- 


ican  Ostrich   (Plate  II)   and  tlio  Cassowary 
(Plate  III). 

((•)  Bicolorcd  or  muUicnlorcd  fundi  dcroid 
of  risihic  hlood-rcssels  are  but  infre(|uently 
encountered.  The  fundus  of  the  Nubian 
Ostrich  (Plate  I)  is  mostly  of  a  light  chocolate 
shading  to  red;  also  the  Bluebird  (Plate  LI) 
exhibits  a  background  mostly  light  gray-l)lue 
but  has  also  a  small  red-brown  area  or  zone 
dotted  with  l)lack. 

B.  The  rasrnlar  fundus  oculi  is  one  in 
which  the  choroidal  rnpillarics  show  more  or 
Icsx  distinclhj.  In  some  instances  the  blood- 
vessels are  barely  visible;  in  others  they 
cover  the  whole  background  and  are  the  most 
conspicuous  objects  in  it.  The  vascular  fun- 
dus is  subdivided  like  the  avascular  back- 
ground. 

(a)  Lii/lil  ijrai)  or  gniii-hhir  fundi,  more 
conmion  than  A  (<;),  arc  found  in  the  Wheat-ear 
(Plate  LID,  the  Cormorant  (Plate  XXVIII), 
and  the  Glossy  Ibis  (Plato  XXIII). 

(/))  Dark  gray,  drcp  (iroy-hlur  or  slalc- 
colorrd  vascuUir  fundi  constitute  the  com- 
monest exami)les  of  colored  fundi  so  far  s<-en 
by  the  writer.  They  are  found,  among 
others,  in  the  European  Cuckoo  (  Plate  XLV). 
the  Wonga  Wonga  Dove  (Plate  IX),  the 
PuHin  (I'latc  XV),  Sulphur-breasted  Toucan 
(Plate  XLVl),  Spoonbill  (Plate  XXV),  Croat 
Spotted  Woodpecker  (Plate  XLVIID,  Blue- 
crowned  Jay,  with  a  greenish  tinge  (Plali- 
LVD.  Common  British  Hla<kb;,,!  (Plate 
LVID,  the  Night  Heron  (Plato  XX),  Ameri- 
can.labiru  (Plate  XXIV),  Law  Bird  of  Paradise 
(Plate  LV),  Lammergeier  (Plato  XXXII). 

(c)  Ycllon\  orange  or  nriiiilion  fundi  show- 
inij  choroidal  Mood-rcsscis  are,  as  in  the  .V'f' 
class,   found   almost   entirely   in   birds   with 


\U 


CLASSIFICATION   OF  THE  OCULAR   FUNDI   OF  BIRDS 


113 


nocturnal  habits.  Amoiij;  them  are  the  Bra- 
zilian Boatbill  (Plate  XXII),  Kakapo  (Plate 
XL),  and  the  Barn  Owl  (Plate  XXXVIII). 

(rf)  Vascular  fundi  whose  general  culora- 
Hon  is  brou'n,  brownish  or  russet  are  also  fairly 
common.  The  White-bellied  Sea  Eagle  (Plate 
XXXIV),  Gila  Womlix-eker  (Plate  XLVII). 
LanRhinK  Kingfisher  (Plate  XLIIi,  Little 
Bustard  (Plate  XXXVI),  Raven  (Plate 
LVIII),  Stone  Plover  (Plate  XVII),  Creat 
Blackbacked  CIull  (Plate  XVI),  Blue  Snow 
(Joose  (Plate  XXVII)  and  the  Chimney 
Swallow  (Plate  L)  are  among  them. 

(p)  liieolored  or  mullivolured  raseulur  fundi 
are  commoner  than  those  classed  under  A  (c). 
The  vascular  eyeground  of  the  Martiiieta 
Tinamou  (Plate  V)  is  brownish  below  and 
light  gray  above;  its  color  scheme  reminds 
one  of  the  ocular  background  (when  seen 
ophthulmoscopically)  of  some  nuimmalian 
fundi.  The  Australian  Pelican  (Plate  XXX) 
has  a  fundus  ocidi  which  is  russet  below 
gradually  shading  to  grayish  above.  The 
eyeground  of  the  Kagu  (Plate  XVIII)  is  also 
reminiscent  of  mammalian  color  mixtures;  the 
lower  half  of  the  background  is  a  well-marked 
red-brown  dotted  with  black  pigment,  while 


the  upper  segment  is  a  sky  blue.  The  lower 
two-thirds  of  the  fundus  oculi  of  the  Brazilian 
Serieina  (Plate  XIX)  is  biownish,  the  upiH'r 
third  slate-blue.  The  Bald  Eagle  (Plate 
XXXIII)  has  also  a  mixed  fundal  coloration; 
being  dull  red-brow  n  below  and  mottled  gray 
above.  Finally,  the  eye  of  the  nocturnal 
Nightjar  (Plate  XLIV)  mimics  to  some  extent 
thefini<lal  color  distril>ulion  in  the  background 
of  certain  of  the  night-in-owling  niamn'ali.in 
Carnivores,  being  dark  orange-red  below  and 
light  orange  above. 

In  the  above  classification  the  colored  dots 
that  hesprinkle  the  fundus  picture  of  practically 
all  Birds  (and  represent,  probal)ly,  the  colon-d 
droplets  of  the  retina)  are  not  considered. 
However,  both  <lirectly  and  by  contrast  they 
greatly  modifj  the  color  impression  made 
upon  the  observer,  and  especially  when  they 
are  large  and  numerous,  iuHuence  the  general 
chromatic  elfect.  In  some  instances,  their 
number  and  distribution  are  su:li  as  to  detir- 
mine  the  verdict  of  a  first  glance,  anil  the 
observer  nmst  be  on  his  guard  not  to  mistake 
the.se  accessory  pigment  points  for  the  solid 
background  of  color  which  one  fimls  in  all 
avian  fundi. 


ClFAITER  XI 

THE  OCl  LAR   FUNDUS  OF  BIRDS  IN  ITS  RELATION  TO 
A  CLASSIFICATION  OF  AVES 


TiiF.  writtT  is  well  awaro  of  the  controversies 
>o  easily  ])rov(ikeil  in  that  zoological  storm 
centre,  the  svstennilic  clas>ificalion  of  Hinls, 
lint  he  believes  that  as  the  fnnilus  appear- 
li.-es  in  wild  species  ,ire  probably  invariable 
and  that,  as  the  evidence  so  far  produced 
shows,  each  species  exliil)its  a  bnckgronnd 
picture  distinct  in  one  or  more  particulars 
from  every  other  specii's,  it  is  possible  to 
identify  many  of  them  by  the  use  of  the  oph- 
llialmosco|)e  alone;  in  other  words,  in  the 
classification  of  Hirds  the  fundus  details, 
including  the  varied  coloration  of  the  eye- 
ground,  should  Ih-  considered  quite  as  mudi 
as  the  histology  of  any  organ  or  division  of 
tlie  body. 

The  extent  to  which  these  taxoiiomic  indi- 
cations correspond  to  the  orders  ui  any  par- 
ticular classification  cannot,  in  the  absence  of 
a  complete  or  nearly  complete  investigation, 
now  l)c  determined.  In  the  opinion  of  the 
writer,  however,  there  are  certain  facts  that 
have  arisen  in  the  course  of  this  preliminary 
research  tliat  are  worth  discussing  for  the  light 
they  throw  upon  and  tlii  aid  they  may  give 
to  a  systematic  arrangement  of  avian  siK-cies. 

That  the  eyegronnds  of  the  Riililc  orders 
present  peculiariti<'s  that  distiiigui:h  them 
from  I  he  (uriitiitir  is  evident  at  a  glance.  On 
the  iilher  hand  tiiere  are  the  usual  ditfcrences 
belwcen  the  acarimite  species.  The  colora- 
tion of  the  fundi  and  the  characters  of  the 
pe(t(iis  in  Khea  ( I'lale  II)  and  Slrulhio 
(Plate  I)  bear  a  close  resemblance.  The 
ocular  fundus  of  the  Cassowary  (I'late  III) 
is  more  I  iosely  "Hied  to  that  of  the  Kiwi  than 
to  the  Nandu.  The  ocular  background  ol  the 
Tinamou  is  decidedly  ucarinate  and  this  fact, 


with  otlaT  taxonomie  indications,  justify, 
from  the  ophthalmoscopic  viewpoint,  its  in- 
clusion in  that  subclass. 

The  Apteryx  is  so  decidedly  a  nocturnal 
animal  ^especial'"  in  the  use  of  its  eyes  for 
distinct  vision  boi.  in  the  distance  and  near 
—  that  one  is  not  surprised  to  see  so  much 
ye''iw  in  its  fundus  coloration.  There  are 
s-  V  exceptions  to  the  rule  of  the  yellow- 
ci,.,.red  fundus  in  Night  Birds  that  one  nniy 
confidently  assert  that  the  amount  of  this 
color  in  avian  (one  might  say  in  all  verte- 
l)rate)  fundi  is  in  direct  ratio  to  the  propor- 
tionate use  a  given  species  makes  of  its  visual 
powers  after  sunset.  When  a  bird  and  his 
ancestors  (in  tlu"  evolutionary  sense)  have 
used  their  eyes  for  distinct  visualization 
largely  or  exclusively  at  night  the  fundus  tint 
is  nearly  always  yellow  or  orange. 

Ap|)lying  tliis  rule  to  carinate  Night  Birds 
we  find  many  consistent  and  nnirked  ex- 
amjjles  of  it.  For  instance,  all  the  Strigi- 
formes  so  far  examined  have  a  preponderance 
of  yellow  in  their  eyegrounds.  Without 
carrying  this  assertion  too  far  we  note  that 
in  semi-nocturnal  Owls,  like  Slrix  flainmea 
{Plate  XXXVIII),  the  red  tints  overpower 
the  yellow  and  a  shade  of  orange  results. 

Still  more  suggestive  are  the  fui<dal  con- 
ditions seen  in  the  Owl  Parrot,  Stringops 
hdbroptilii.i  (Plate  XL).  Compare  the  fun- 
<lus,  esjK'cially  its  yellow  color  and  the  posi- 
tion of  the  (temporal)  area  eenlr'jlia,  first 
with  that  of  any  Owl  and  then  with  I'sittieim 
(iiniizona;  undoubte<lly,  so  far  as  the  eyes  are 
concerned,  they  belong  to  the  former. 

.\nother  observation  of  avian  fundi  seenis 
to  show  that  an  admixture  of  yellow  (in  the 


114  1 


CLASSIFICATION-  OF  AVES  AND  THE   FIXDIS  (KTLI 


form  of  an  oriniffe-rcd  cDloration)  may  Ix- 
pn-sciit  til  inilicatf  mil  sii  inucli  ri'cciit  as 
fornuT,  i.e.  atavistic,  iii)j;ht  liiilills  intin  ^in(■^■ 
aliaiiildiicil  liy  the  spcrics. 

Tliis  aliiKist  uiiivfisal  (icourroiicc  (if  yclldw 
<ir  (iranK<--litil<'il  fundi  in  XiKlit  Hirds  leads 
<in<>  to  spccnlatc  as  to  the  cause  .if  a  dlirerent 
coloration  in  species  that,  ilurinf;  historic 
times  at  least,  have  Used  their  eyes  larj,'ely  or 
exchisively  after  ihirk.  At  least  >nnie  of  the 
Ardeiformes  fiirnisli  such  examples.  The  fun- 
dal  colorinj,'  of  \)/(iin)r(U-  inictininti  (Plate 
X\)  has  no  yellow  in  it ;  nor  has  the  Hoatliiil 
iCiinrriiiihi  ri,fhl((iri(i).  allhoiii;li  lioth  fundi 
are  evidi  nlly  so  cJoNely  allied  that  one  might 
well  lielieve  that  tiiey  are  liotli  Herons. 
Proliahly  the  .\ight  Herons  have  adopted  an 


115 

ex<-lnsively  iKK'tnrnal  lif«-  at  sikIi  a  recent 
Keoloi,'ic  period  llial  the  evolutionary  tissue 
changes  necessary  to  produce  the  yellow  fun- 
dus tints  liave  not  yet  lieeii  liroujiht  alioiit. 
The  same  remark  is  applica'ile  to  the  Hit  tern 
(Plate  XXI). 

So  far  as  exann'ned,  the  decidedly  nocturnal 
CaprinMil^ridie  also  have  yellow  or  oran^'e 
fundi.  The  eyeground  of  the  Furojiean 
-NiKhtjar  (Plate  XLI\')  is  a  conspicuous  and 
lyjiical  examiile  of  the  colored  finidns  of  a 
true   Xij;ht-feedin;;  liird. 

The  arranjienient  of  the  centres  of  distinct 
vision,  the  fundus  tints  and  the  pectinate 
tissues  of  the  lar),'er  Acciptrifiirmcs  present  a 
decided  (iphthalmoscopic  resemlilance  in  ail 
the  sjH'cies  so  far  <'xaniined  liy  tlie  writer. 


CHAPTKR  XII 

RELATIONS  OF  REPTILIAN  TO  AVIAN   FUNDI 


The  colored  illustrations  of  three  eyegrouiuls 
of  reptiles  are  pulilished  by  the  aid  of  Mr. 
Head  and  through  the  courtesy  of  Mr.  Lind- 
say Johnson.  In  this  text  are  also  included, 
for  purposes  of  comparison,  two  black-and- 
white  drawings  of  nianinialian  'andi.  One  of 
these,   the   t'oininon    Uedge-Hofj   (Fi^.    lH!) 


■ig.  143 

Kiiiidiis  Oculi  of  tlie  Common  Hedgehog. 
(After  Lindsay  Johnson.) 

reminds  one  of  the  Indian  Cobra  (I'late  LXI), 
while  the  fundus  view  (Fig.  144)  of  the  \ir- 
ginian  ()pi)»uni  suggests  the  backgminid  of 
the  Iloiiied  Toad  (I'late  l,X).  In  other 
Words,  th(-.e  two  reptilian  fundi  have  more 
marked  allinities  with  other  vertebrate  elas.-es 
than  with  Birds.  On  the  other  hand.  Were  it 
not  for  the  absent  macular  region  and  the 
greater  jjroniinence  of  the  radiant,  retinal 
nerve  lib-  ■;.  the  ocular  fundus  of  that  noctur- 
nal lizard,  IIiiirdudi/liiH  tiirciciis  (Plate  LIX) 
might  be  regarded  as  an  avian  form,  rather 


closely  related,  for  example,  to  the  Kiwi 
(I'late  IV). 

.V  reference  to  the  proliable  evolutionary 
connection  between  Birds  and  certain  sub- 
orders of  Reptiles,  as  indicated  by  their 
ophthalmosco|)ie  pictures,  has  already  been 
made.  It  may  eventually  transpin-,  as  indi- 
.  d  by  this  "straw"  of  evidence,  that  the 
(hrkiitidir  are  comparatively  near  relati^'es 
oi  the  primitive  Bird,  while  other  lacertilian 
suborders  and  the  Opiiidia  are  as  far  removeu 
from  them  as  the  Marsupials. 

A  iletailed  lescription  of  the  three  rei)tilian 
cycgrounds,  rei)resenled  in  the  Atlas  by 
colored  reproductions,  now  follows. 


Fig.  \U 

Fundus  0<-uli  of  tlic  ^ 
(After  I.iud.-' 


in  Oooasum 


116  I 


wim. 


TUK   HKLATIONS  OF   HEITILIAX  TO  AVIAN   FrXDI 


117 


Reptilia 
TruKisii  (iKCKo.  Itcniiilncliibis  liirrlni.t, 
V.rvvi  iiiijiKc;  left  vyr.  The  fiimliis  .nppvar- 
aiiccs  (I'ljitc  LIX)  of  this  nocturnal  lizard 
rcniiiKJ  one  of  the  Kiwi  (Plate  IV).  The 
orange-red  liaekjjround  is  uniformly  (lotted 
with  dark  .sp(<t.s,  while  the  cireular  papilla  is 
coi:i|>letely   ohscured    l)y   a    ehocolatc-browii 


I'ij;.  1  t.-i 
IVclpii  of  ii  Tiirkisli  Gei'lii)  {Itermuladi/lu.i  tun     ii.i). 

pecten,  whose  pointed  free  end  projects  a 
medium  distance  into  the  vitreous.  There 
are  no  si>;ns  of  retinal  or  choroidal  vessels. 
Clearly  defined,  white  lines  (opa(|ue  nerve 
fibres)  radiate  from  the  disc  margins,  Riving 
the  elFeet  of  a  halo  about  the  central  zone  of 
the  picture. 


A  Internl  view  of  the  Gecko  pecten  is  seen 
in  Fig.  H.'i;  it  is  .suggestive  of  a  similar  view  of 
the  Aptcry.x  ix'cten  (Fig.  i7}. 

IlfUi.NKi)  To.\n.  I'liryiiofiomii  riiriniliiiii. 
Plate  LX.  I^'ft  eye.  Erect  image.  The 
color  of  the  fundus  oculi  is  a  dark  slate,  irregu- 
larly strewn  with  minute,  whitish  dots  of 
various  sizes.  There  i.s  an  ill-defined  macular 
rcijioii. 

The  i)ear-shaped,  grayish  papilla  has  n 
white  margin,  from  which  short  fibres  of  u!i- 
c(|ual  length  radiate  towards  the  periphery. 
.\  single  ce!itral  (?)  artery  seems  to  originate 
from  the  nervehead  and  with  its  six  branches 
—  two  on  one  side  of  the  disc,  four  on  the 
other  —  ;*  supplied  mostly  to  the  lower  half 
of  the  eyeground.  .\bove,  a  small  branch 
anastomoses  with  a  twig  that  runs  from  the 
periphery  of  the  field. 

I.VDi.v.v  CoBH.v.  Xaia  tripudiaii.i.  I'hite 
1>XI.  Left  eye.  Erect  image.  The  general 
coloralinn  of  the  fundus  of  this  Snake  is  light 
gray-blue,  .sparsely  dotted  with  pigmiMit  of  a 
similar  but  deeper  color.  The  whole  back- 
ground is  regularly  covered  with  opaque  nerve 
fibres  who.se  radiate  disposition  reminds  one 
of  Merula  (Plate  LVII).  From  the  button- 
like nptlr  di.ic  arise  three  vessels,  apparently 
two  arteries  of  small  size  and  one  (larger) 
vein.  The  centre  of  the  papilla  shows  the 
reniains  or  the  undeveloped  tissues  of  a 
pecten. 


-^'W^, 


jjr 


y.r'^iiij'L^ 


ClIAITKU   XIII 


( OI.OUKI)     l)HA\VI\(;s     Of     TIIK 
()(  I  LI   OF   mi{l)S 


FIXDIS 


Kkkohps  III  iliiplicatc  cxiiclly   tlic  piiiiiliiiKs  niiiilc  l>y 
Mr.  A.   W.   Ilfiul    for  this   Athis   Imvc  Ihmmi  iilli'iiilcil 

l>.v   (liflinillics   Ihul    Imvc  iiriscii   iliicfly   fi I|i<-   r,i,| 

lliiit   />rcm,    <lii|>li('iili< f  iiiirintc  drljiils  mid  >liji(lcs 

of  ci.ldr  uif  niiiicir  iiniMirliiiicc  in  llie  iisnnl  roriiis  of 
ciilor  rt'iinxluclioiit  were  rcKiirilrd  as  csscnliiil  in  this 
iiivosli«iil=oii.  However,  ll -se  itnpedinients  were, 
.ifter  niiiny  trials  and  the  exereisi^  of  iiiiieli  patience  on 
the  part  of  the  pulilislier's  oHieials.  final  reniowd  and 
the  writer  now  helieves  that  the  follow  plates  failh- 
fiillv  represent  not  only  the  varied  and  Iteantifnl 
eoloration  liut  the  complex  lissne  fornialions  revealed 
l)y  the  ophlhahnoscope  in  the  ocular  liackijroiind  of  the 
avian  ami  reptilian  species  hereirr  depicted. 

For  the  convenience  of  the  reader  a  hrief  description 
of  each  fniidus  drawing  has  heen  placed  on  the  pafje 
opposite  each  plate,  a  more  complete  description  of 
the  o|)lithalniosco|)ic  appearances,  as  well  as  their 
relations  toother  fundus  views,  hein^  fliven  in  (hapler.s 
IX  ami  XII. 


!i 


1  no  I 


RATITiE 
Struthioniformes 

N'lmw   Osiiiirli.      Slnilliln  rdiiiilii.t.      I'liitr  I. 

Till'  ;;i-iii-riil  culiir  nf  llii-  I'Vi'^rniiMil  is  iliill  rril.  Iti'siirinklril  willi 
iJKlili'r-rril,  riiiiiiil  ilnls  tiiiil  uf»y  Kriiiiiili's.  TIh'  luwi-r  liiilf  of  llic 
fiiiiiliis  ;ip|M'iir>  viiiirwiiiil  uriiyrr  ill  Iniir  lliciii  tlir  ii|)|M'r  ■.rrliir".. 
'I'liio  M|)|H'aniii<'f  is  pmliiililv  iliic  li>  tlir  tiiiliicriiiis  o|iiii|iir  iirrvr- 
tilil'i's  llial  i'Vli'liil  rnilii  iill  siiii's  of  tlir  |iii|iilhi  jis  a  ri'iilrc  iicriiss  I  lie 
I'liiiiliis  111  llic  |wri|ilicrv  of  I  lie  (iciiliir  liii«k)jrimnil.  Tin'  ml  colorii- 
liiiii  of  till'  fiiiiilils  is  si'i'ti  to  lie  iiiiiri-  iiilriisc  liiwariN  llic  ii|i|irr  liiill' 
of  the  cyfurumnl.  Tlit-  optic  iicr\c  ciitriincc  is  very  liroail  ami  oval 
ill  shape.  The  margins  of  the  iicr\i'  head  an*  very  «hile  ami  il  is 
possilile  with  the  mirror  to  see  all  aroiiml  Ihc  pecleii.  The  centre  of 
the  liisc.  iiicluiliii^;  the  parts  near  the  root  of  the  pecleii.  arc  slippleij 
with  miiMite  lirowii  pi^jiiient  liots.  like  Mack  |K'p|M'r  jrraiiis.  The 
pecleii  presents  the  ap|H'arance  of  a  iinmlier  of  iliill,  dark,  scpia- 
lirown  tiihereles.  Il  iIih's  not  project  far  forward  into  the  vilrciiiis 
cavity,  while  its  outlines  and  contour  may  lie  disliiiffilished  liotli 
aliove  and  lieliiw  th"  disc.  The  |H'etiiiale  margins  are  formed  of 
round,  ovoid  projections  The  macula  is  mil  very  strikin;;  in  appear- 
ance, and  takes  the  form  of  a  crescentic  arranjremcnl  of  miiinte. 
V'ray  dots.  It  is  seen  Inwards  the  nasal  side  of  the  disc  near  its 
upper  end. 

Rheiformes 
.\mkh  (  AN   (IsTHli  II.     Hfiiii  itiiiirictiiiii.      Plate  II. 

The  <'oloralion  of  the  fundus  as  a  wliole  is  liiitf.  nier).'in^'  into  iliill 
red  at  the  periphery.  Il  is  stipph'd  all  over  with  iiiinille  dots  of  a 
li;;liler  lint. 

The  optic  disc  is  maile  up  of  while  ami  coarse  nerve  luindles  that 
cxhiliil  a  faintly  detincd,  friii;,'e-like  liordcr  all  aroiiml  its  mar^iiiis. 
liadiat  in;;  for  a  distance  of  alioiit  two  disc-lireadlhs  across  the  fundus 
,irc  a  few,  dull-nray,  opa(|Ue  nerve  filircs  thai  finally  disap|H'ar  into  the 
liackKround. 

The  macula  is  situated  slijfhlly  aliove  and  to  the  nasal  side  of 
the  optic  papilla.  It  is  somewhat  ;;raycr  than  the  siirroiindin^' 
cye;.'niiind:  aliove  Howards  the  outer  side)  and  liclow  the  fovea  are 
a  few  pale,  liri^ht  ^reen  reflex  lilies. 

The  pi'ctcn  is  a  massive  orjjan  with  saw -like  mar^'iiis.  Ihc  serra- 
tions liciii;;  of  a  li;;hter  hrown  than  the  central  liody.  The  lower  pari 
of  the  pcclcn  is  sonieuhal  cluli-sliapeil.  ;iiid  comes  well  forward 
toward  the  posterior  capsule  of  the  lens.  Mctwceii  Ihc  projcclin;; 
li'clli  of  Ihc  iM'<tinate  serrations  may  lie  seen  a  sli^lit  stippling'  of 
pif;nieiit-like  lilack  pepiMT  grains. 


l-.iii  1 


•'-J. 


il^t-, 


''iife  iL"i-'ihMiLA'i!St>^- 


V  V* 


-i'-'. 


l£iJ   i--i 


RATITVB 


Struthioniformes 


Platk  I 


Striilhio  cdm.hiit 


Rheifonnes 


Platk  II 


Hliid  amiTicana 


■->'*'"'^T^.WW-. 


RATITiE 
Casuariiformes 

\\  l>ri  IIM  \S    <' \»".ii\\  Mi\  ,      lifiiiiriiis  luiiliihili.i.       I'l;ili|||. 
The-    fllVMI  riilnnrl    rM'^rKlllllI    i-    ciiMTcil    uilli    II    liijlililr,    -ilMT- 

Kiiiv  »li|>|ilr.  ill  llii'  fiirin  iif  tin--.  -.In.rl  linr-  uilli  llirir  Imi),'  ii\r- 
I'liiiliilii.'  ill  :i  M  rtir;il  iljri'i'l  jii;i.  A«  IIiim'  iIiiIIiiI  liii<'>  .ippriMirli  llir 
iiiMriihir  ri'uiiiii  I  liry  Ihtiiiik'  iiiorr  iiml  iniirr('iiii\i'ru;<'iil  iiiilil  tlirv  roriii 
n  lirilliiiiil  chi-lcr  III  III!'  fiivi'ii.  'I'luir  i-  iii>  vUililr  liiu'  nf  ilriiiiiriii- 
I'liii  or  r.  tlf\  riiiu  -I'lmniliiiu  llii'>  iircii  fnnii  llir  m'lirrjil  fiiiidiiN  nrcii. 
Tliili'  illT  lici  \i^llll(•  I'liiirniiliil   \r»vU  i«r  ii|iiii|iir  ll<r\r  llliri'-. 

'I'lii'  i>|itir  ilJM'  is  liiiii.'  Hiiil  liiiiil -•.|iii|ii'i|.  uilh  II  ri'i|ili-li.  ii|i|iiir- 
i'iill.\-  cuiiiiivrccMlrr.  1 1  i>  iiiiiri.rinl.v  >|>iiiiklri|  t\illi  iliiikir  nil  di.ls. 
wliirli.iis  llii'V  M|i|)rii,ii'li  till'  iM.'iri.'ili  <il  Mir  piipillii.  lire  iniirr  rliiM'ly 
liiiiki'il.  Mini  ]i\\v  llir  ii|>|H  iinilK')-  of  ii  >li.i(liiu  <'ii>l  nil  iiliiiiil  llii' 
ililiiv  i-(l;.'i-  (if  till'  ili,c.  Till'  iiiiiryiii-  of  lli  •  lirrM'-liriiil  :iii-  di.- 
lilK'lly  white.  Iiiil  \\\vy  Iimvc  iml  Ihr  "tiliniii<>  '  iipiMiiniiii  r  mtii  in 
iiiiiol  iix'iiili  iiiicktiriiiiiiils. 

Tlir  clKPCiiliilc-liniHli  I  hmI  I  11,  111  IK  1 1  liiiijiilcr  jil  ils  li.isc  Ihiiii  .il  llir 
ii|M'\.  iTM'iiilili^  M  coikMiiw,  iU  hiliinl  riiMiliiiii  liciiiy:  ii'>l  iiiiliki'  ii 
icickMiiiiili.  willi  iN  >i\  «(  TliiliniiN  riillliilril  nil'  ill  llir  :ip(\.  'I'wci 
(')'iilriil  vri'iiliniiH  ciiiiir  well  fiirwiini  liiuiiril>  llic  Icii^. 


Apterygiformes 

M  will. I,  .\l'|■^.ll^\.     .ti)l<ri/.r  miiiililli.      I'hilcIX. 

'riif  ociiliir  liiickfiroiiiiil  i-  iiiiifornily  .iiiiii;,'«'-rri|.  »ciiiic\n  li.il 
iiKilllcil  with  l.idwii.  'I'lic  lirilliiiiil.  uliilc.  I'uiiiKJ  ilix-  i-  niiiiipiiihIimI 
liy  >liciil.  (i|i:ii|iii'  iici\c-lilirr  l.i,\ri>  mil  ciilirrly  ckvitimI  liy  I  lie 
fflii'-l  rjilcil  liiiM-  of  I  111'  Ion;;.  Iiir;;c.  iiiiil  coiiiiitl  |M>(lrii.  «  Iiom>  |ioiiil('il 
(•ml  iciiclio  iiliiio^l  III  till'  jells.  'I'liere  iiie  no  >iiriis  of  eliiiroiijiil 
lilooil-N'esx'U. 


I  1«  I 


RATITiE 


Casuariiformes 


I'l.VIK    III  ('(l.illitrill.i  orripiliilln 


Apterygiformes 


Vi.vn:  IV 


Aplcrii.!'  iiiriiifrlli 


mmss!^ 


RATrr>E 

Tiiumiformes 

M\llllNKI\    'I'lNWIlH.       rd/lx/niWd/  (7((/<l(/.«.         I'llllc    v. 

Till'  liiirkuriiiiiiil  rnliiriiliiiii  i»,  in  llic  tiiiiiii.  ii  ili'i'|)  univ.  tlir  Iiihit 
liiilf  iiiiTKiiiu  into  (lull  oriiiiui'.  Tin-  wlicilc  of  I  In-  riiiiili  U  tnMTfil  liy 
II  I'lilli'i'lidii  i>f  liny  iliilo  piirki'il  cluM'lv  liiui'tlirr.  In  llir  n|i|»<r  Inilf 
i>r  I  lie  tii'lil  llicv  lire  Hliitc.  Iinl  rnini  I  he  rruion  ■>(  tlir  iliv  uml  iliiwh- 
«iinU  llii',\  iHM'iinii'  ii  ilnll  urinurr  nilniir.  (  nxoiiiu  llic  fnnilii'*  iiml 
riinninu  vrrtiiiillx  mi  cilliiT  >ii|c  of  I  lie  |iiitiillii  iiri'  wmtiiI  iiniiiur-ri'<l 
I'liiiroiiliil  \r«M'li, 

TIh'  nnirlllii  iipiM  irN  iii  i  iliill-unix  iiiim,  willi  ii  lirilliiinl  uliilr 
ci'litriit  s|Mil  <.iirriiiiii<li'<l  li.\  ii  oiiiiill.  iiinl  n  piilc-uncn.  •.Ii-nikcd, 
rrlliA  riiik'.  Il  i«  pliiinlx  vi-ililr  mi  iIh'  niiiiil  -.idr  nf  llir  imtIcii. 
Till-  iiplic  IK  r\r  ix  umiI  in  ■.Iiii|k'  iinil  tAci'pliiiniillv  liroml, 

'I'lir  lllil-.-.  iif  Ilir  iMM'Icn  iilinix.1  riinipli'lrl,\  rovrr*  llir  iiplic 
piipilLi.  uhii'li  i-.  i|iiil)'  wliih-  iiinl  liHiks  like  ii  iiiiis-.  of  fiiiirM'  iipiii|iii' 
iiiTvi'  tilirc-..  The  opiic  iiiiirKiii'  iirr  Imrdrrril  with  uriix  piuiiicnt. 
frmii  whiili  spring  n  few  »|iiirt  iiptii|iii'  iiitvc  tiliri'«.  Tlir  imtIcii  i« 
•  ■liiHiiliilc  lirowii.  mill  ill  iiilililiiiM  Ik  ils  ni.iNsixr  iip|H'iiriini  r  i-  inmli 
"Imrli'i'  lli.'in  llir  Miirir  nrunn  in  nm^l  nf  llii-  liinN  i-\iiininr<|.  Il  i-. 
<Ni'>y  III  MM-  lliiil  il  is  frinui'il  mII  rmiinl  willi  puinli'il  lull...  Ili.il  llic 
rcniriil  pnrlimi  or  riiltfi'  i-  ■.rrralnl  iinil  lliiil  il  i-miii'i  will  fnrwiinl 
liiWiiriU  till-  li'ii-.. 

CARINATiE 

UaUiformes 

\' miuki.i,  Ci  II  \-<Hiiw.     <'r<ix  ijliihiiKii.     I'liilr  \'l. 

Till-  i-yi'Krminil  is  a  iliill.  Iiinlrn  t'l'iiy.  cnvrrrd  willi  liny,  wliito 
dots.     Tlicrr  arr  nn  visihir  rlimiiidal  vrssrls. 

Till'   papilla   appears  as  a  ImiK  o\al.  wlmsr  cmilral   /. is  dull 

oraiiK'i'  iniiiKli'il  »illi  iiiiniili'.  dark-lirown  ilnls.  Il  alsn  prcsmls  n 
marginal  frin«i' of  wliilr.  A  U-w  upaiiur  ii<-r\r  tilircs  cxlciid  on  rilliiT 
sidf  nf  llir  disc  arross  llir  fundus,  liiil  for  a  sliurl  ilislanir  mily. 

Tlir  imtIcii.  iif  spiral  fiirin.  is  ciilorcd  daik  cliiiciilalc-lirnwn.  1 1 
sci'iiis  III  la|MT  ijuilc  ilcciilcdiy  where  il  jnins  I  he  disc,  and  luuks 
like  Ihe  riMils  of  a  Ircc  at  ils  dishil  end,  where  I  he  riiiillcts  liury  llicni- 
sclves  in  Ihe  disc.  .Iiisl  aliinc  Ihe  disc,  smue  little  distance  In  Ihe 
nasal  side  nf  the  |M'ctcn.  is  a  rniinil.  crey.  snflly  mitliiied  area  near 
which  is  seen  a  well  iiiarked  reflex  nf  a  p;ile  Miie-jjreeii  Iniie. 


1<4 


>5«HBF?i'tirns«RnffvrA9r^!ik^; 


i...  t ,, 


-^•:t 


ff-ir;'t 


■•:iy>T^:f5i«:s- 


Th\f  *:>i-. 


Tinamiformes 


I'l.MK    \' 


('iiliiihn'ti'i  il,(iaii.i 


CARINATiG 


U 


r  Uiformes 


I'l.AlK    VI 


Craj'  (jlohona 


liigm^M^m. 


}9f 


"^'''iim.'^K^...mi 


CARINATjE 

Galliforiiies 
|{|(l  -11    Tl  likKV.      Ciillirhin/.i  Idlliiiiiii.      I'liitf  \'II. 

Til.'  lycmdiiiKl  is  dull.  >l,i|y  i-niy.  iiii(lcrlyiii«  luiriilx-rs  itf  fiiif. 
Ii«lil-«i;i.v  (li)l>.  Tlic>(  ,l<i|s  iiic  iMiifdiinly  Mnllcrt'd  ovi-r  the  fundus 
.'Xcrpl  loHjiids  Ihc  unsiil  ,i(|,..  lien-,  on  .i  level  with  tile  superior 
end  of  111.,  optic  iier\e  .1111!  ill  the  diri-etioii  of  the  iiijieiiljir  iireii.  tliey 
Jire  of  11  more  l>riiliMiit  white,  lire  closel.v  piicked  lo^ellier.  iiiid  iire 
lievoid  of  11  retlex-riii^. 

I-Atiiidiiii;  from  either  side  of  the  optic  disc  mid  riimiiiif.'  nt  rijriil 
iiiiirles  to  that  oryiiii  lire  a  lew.  riither  fine,  seliiilninsliiceiil  nerve 
liliies.  which  arc  lost  towiirds  the  jieriphery. 

The  optic  disc,  whose  iipp.'r  end  is  shiiped  like  the  sharp  Ix.w  of 
a  lioal.  appears  to  Ix'  composed  of  a  iiiiiss  of  lirilliant.  white.  opa(|iie 
nerve  (ilires. 

The  pecleii.  of  the  usual  chocolate  lirowii  color,  is  massive  and 

^ "Iii'l    <lul>-sliapi'd.      It    cMeiids   well   forward   towards  liie  lens 

and  tajxTs  rapiilly  as  it  approaches  the  superior  end  of  the  nerve. 

llMil,i:i<i  IN   (^lAii..      ((iliiniir  lil.-ln'oilni.      I'lateVIII. 

'I'he  ocular  l.ackjrroiind  is  lijiht  uray  sprinkled  with  minute 
yiaiiillo.  wlii<li  H:ive  it   the  appearance  of  a  roliKli  surface. 

The  o|itic  iiiMVe  lii'iid  uivcs  one  the  visual  inipression  that  it  is 
foMued  of  Urilliaiit.  white,  short,  <(.arse.  opa(|lle  tihres.      Its  shape  is 

^ii'il-  Ixiiifi  loiij.  and  narrow,  with  a  rather  sirikiiif;  resemlilance 

to  the  project ilitr.  serrated  jaws  of  the  Sword  Fish.  K\tendiii>;  aloliK 
each  side  of  the  optic  <lisc.  at  riyhl  aiij.'les  to  it,  arc  a  few  rather  pale. 
Iliili.  opa(|iie  nerve  til'ics. 

Till'  pcclcii  is  lijihtcr  hrow  II  in  color  t  liaii  usual,  and  is  ver.v  narrow 
ill  its  junction  with  the  papilla.  On  either  mcIc  of  it  are  a  few  miniile 
dots  of  l.rowii  pijiiiieiit.  The  inferior  s<'};nieiit  of  the  |>ecleii  forms  a 
corriii.Mtcil.  liiilk.\  iiia>>  which,  however,  extends  well  forward  into 
the  \itreoiis  cavity  to  I  he  postiM-ior  surface  of  the  lens. 


HH] 


CARINA'.  S 


Galliformes 


I'l.MK    VII 


Cdtlii  turns  liilhami 


Galliformes 


I'l.ATK   \  III  Coliiniij-  liistrioiiica 


CARINATiE 
Columbiformes 

\Vi)M;\    \Vc>\(;\    DiiVK.      I.iiii-ii.iiircid  jiirdlii.       I'lillclX. 

Till-  iiciiliir  liack^'riiiniil  is  nl'  m  iiiiiroriiily  firny  liiil.  While  iluN. 
liirlilirif;  ii|>  the  fiiiuliis.  iirc  x'lillcrcil  over  llic  crilirc  fii'lcl.  A  IV« 
(■li(pri)i(l,il  vessels  iire  In  Ix'  seen. 

'I'lie  iiplie  ili>e  forms  ii  \imfi  i)\.il:  il  ii|>|)<';ii's  jis  if  il  wen-  eiiiii- 
posecl  (if  ;i  (((Heel  ion  ((f  while  fihres.  iilld  I  hesc  seem  hiiiiched  loudher 
l(ir  m1)(iiiI  (die-hiilf  the  len;;lh  of  I  he  l>e(teii.  0|>ii(|iie  nerve  fihres 
ladiide  fndii  the  eireiimfereiice  of  llie  piipilhi.  while  several  oraiiiic- 
rcd  ieli((r((i(lali  capillaries,  iiilerspersed  wilh  pif;merit  dots,  run  on 
either  side  of  it . 

The  pceten  appears  as  an  exeepi  ionally  hiUfi.  cornijialiMl.  dark- 
lirown  mass.  Seen  lhroii>;h  the  mirnpr  from  aliove  il  has  I  he  appe.ir- 
aiiee  of  a  piece  of  larred  r((pe.  The  siniile  Tiiacniar  area  is  seen  hilhe 
inner  side  of  the  disc  and  a  little  al)((Ve  its  upper  end.  The  sheen  of 
the  pale  i;reen  retlex  Ihal  pla\s  alioill  il  when  ilhiminaled  liy  the 
li;;hl  of  the  ophthalmoscope  looks  like  watered  silk.  The  foxca  has 
the  appearance  of  a  small  ^'rcen  flare.  soinelhiii<;  like  that  from  a 
hulls  eye  laiilern  seen  close  al  hand. 

Kl  lloi'KAN    Wool)    I'liiKoN.      ('i)hiiiih(i  iMiliiiiihii.s.      I'l.ile  \. 

The  lint  ((f  I  he  ((ciilar  liaekfiround  is  pale  slale-yrax .  The  eye- 
Uroiliid  i>  eo\('red  with  very  small,  dull-while  dots,  so  that  the  w  hole 
fundi  I-  presents  a  lif;liler  shade  of  jrray  I  linn  it  otherwise  wdiild.  On 
the  lower  half  and  each  side  of  the  optic  disc  ar"  seen  several  oranj;e 
col()re(l  choroidal  vessels,  which  liec((iiie  more  mimeroiis  a^  one 
approaches  the  [)eripliery.  FAlendinj;  al  rif;ht  anjjlcs  to  the  papil- 
lary margin  are  a  few  oiia(|iie  nerve  f'lires. 

.\  little  ahove  the  superior  end  of  the  ofitic  iierv  ■  head  and 
towards  the  nasal  side,  is  a  small,  round,  aiiparcntly  somewhat  de- 
pre-scd  macular  area  of  a  diill-iiray  tone.  From  its  mariiins  run 
a  (l((iil)le  row  of  tine.  l>hie-j;reeii.  Iraiisliicent  lines  which  form  alioiit  it 
a  lirokeii  or  irrcuular  reflex  rinj;.  The  liird  hecomes  nmisiially  resl- 
le-s  when  the  lij,'lil  from  the  ((plithalnio.scopic  mirror  is  focused  (di 
this  |>art  of  the  fundus.  The  optic  disc  appears  of  a  dead  white 
color,  and  seems  to  have  a  frin>;e  of  short  fihresof  the  same  color  all 
ahout  itsedjies,  \[  the  junction  of  the  pecleil  with  the  Mervc-hcad. 
i.e.,  .(loiij;  the  central  area  of  the  latter,  one  sees  niiiiicroiis  Inown 
pigment  dots  that  ap|)ear  like  small  rootlets  or  capillaries  and  tiwr 
,1  relicniate  ap|iearance  to  the  papilla. 

The  pecten  itself  has  a  dark  chocolate-lirow  n  color  and  a  cork- 
screw contour;  it  is  unnsiially  lonj;  and  carrow.  and  its  lower  sedi- 
ment appears  to  come  well  forward  towards  the  lens. 


I  HH 


^^S^^^^^^^&m^.  ':e-im^m^m 


CARINATiE 


Columbiformes 


Pr.vii;  IX 


f.ciifo.iarciii  iiiciilii 


Columbifonnes 


Pl.ATK    X 


('i)liiuiliii  juihimhii.t 


CARINATiE 
Columbiforiiu-s 

Nil    liiIlM     (    I.MiWMIl     I'll. Ins.       (iiiiini   lir/iiriil.        I'lillc    \l, 
'I'lii^   riilhlii"  I"  uli   is  i,r   llii'   liWiy   cdldr.   >rrii   i;i'iiiT,-ill>    in   |iii:ciiii> 

111  hi    .|o\,>.    ;||hl    clAlTl'li    W  ll  ll    IIIIMIlll'    U  llilc    (|(lK,         (>||    |  ||i'    ll|l|>c|-   ,111(1 

ii.i-,il  -iilr  ..r  I  III'  ruiiiliis  is  I  lie  iiKi(iil,-i,  ;i  siniill  (llill-m-:i>  :irc:i  siir- 
iciilinli'il  l.\  .1  -ni\  .'iiiil  L;ri-cii  icllr\  (.1'  siiiiill  liiii'~.  'I'lic  iiplic  .|i>c  i> 
Iciiii;.  ii;inin\.  In  i,il --.li.iiicil  ;iiii|  ■.iiiiicw  li;il   niiiiiilc'd  ,il   IIh-  ii|>|>i'r  cikI. 

Il     liH.k-   ;i,    ll    \\r\<-   IMllli-r   liiilliiu    ;iMi|    i;lilV    ill    llir  crllll-c    uilll   II    uliilc 

'iiii  .ill  iiiniiiiil.  \  iiclucirk  (if  sIiimII.  Iiniwii.  piLtini'iil  cliil>  is  dis- 
|Misii|  .il.iiii;  llic  'iiilic  III!  filliiT  si(||.  ,,(  ihr  |i|.||i'ii:  Mild  siiiiic  i>|iMi|iii' 
llil\c   li'>ris  r\lclid   ;lrl    pss   III,-   llllldlls  on   .ill   sides  i,(  III!'   llc|-\r. 

Tlic  pfclcii   is  1,1    ll  ,■  iisii.il  d.irk  cIkiiiiI.'iIi'   liiil.       Il    is  ciirkscri-u- 
likr    ill    :l|p|M,ir.iiii c,    lull    (,ii(.   ,  ..,      is    nilllcl-  rlllli-sli;i|H'd   iind    liinks   Ms 

ll'  il    vM-n-  ecu, red   Willi  -'iiiill   lunui Iiilc-s,      'I'liis  sc-yiiH'iil   ionics 

niMi-,.   |ir iiiciill\    Inruiird    Inuiiids    l|i,-   li-ns. 


RalliforiTies 

(    lil  -n   I.    (    C.I.I.        r,,!',,;,    rri.s;,lla.         I'hilr    \||. 

I'll!'    |.irdi.iinii;iiil    ri.li.i-   i.f    llii'   ivc:;riiunil    is   dull    ■j.rwy  .   rM-r\ - 
wlinr   -|.i  iiiklcl   will,   ininiili-.   whlli-  di.ls   IIimI    .ii-,-   i r  ilnuly   srcn 

.•|lic.\r    III.      sl||M|-i,,r    IrrinilMl  ii.ll    i.r    llli-    o|llir    llrlM'    ;inil    In    I  llr    n.ls.ll 

siili-  ..r  I  III'  pi'ilin. 

'rill-  I.. Hi;  ..|ilic  disi-  i,  u  hill-,  with  M   IVu   lin\    |iiL;iiii'iil   dnl  s  .dM.iil 
Its  in:ii-:;ins.      'I'll,.    |,rilin   is   lii;lilir   Ihiumi    IIimii    in    llic    nniji.iilx    i.f 

I'ii.js:    il    is    \,\\     \.\v^f.    a\\ I    liidini;    llic   disc    t'roin    \icu.      Miiny 

"l'in|ii''    111  i\c   lil.ics   nidiiilc   III. Ill    llic   |>ii|>ill,-ir>    lii-cnnifcrcncc  ;ind 

CVlcIld    si'MTmI    disc    I.Ti'Mllllls    .ICInss    III,.    Inildlls. 


M 


[  I  till  I 


CARINATiE 


Columbiformes 


I'l.vn:   \l 


(!iiiiiii  I  ii-lnriii 


I'l.Aii:  XII 


l-'iilini  cri.iltitd 


CARINATiE 
Ralliformes 

ll'KMix    Umi..      Aniiiiiili.w  ii'iidhii.      I'hilc  \||I. 
Tlic  <y<!;n,iin<l  i-  :i  \.i\    |kiI<'  iiriil'oi'ni  i.'i;iy  ^li|l|l|l'<l  hIiIi  (l;iik<T 
Sr.-iv    ;iiiil  \\lii(r  dciN.  Iliii>  ■i'[\'u\>i  llic  wlii.lc  ticlil  ii  ;;r;iiiMliir  iip|Miir- 
iiiicc.      'I'lic    li(ii-i/^c>riliilly    ,,vi\\    iiiiiciihir   iirrii    mri    Ihc    riii-.iil    .isiiccl 

M<:ir-  Ihi'  ii|)|MT<iicl  (if  thi'dixi  .iN^ CN  ii  i)iMki>li  liiiic.     Al  ilxcnlrr 

i-  I  Mii.ill  |>il  with  .1  Ki'llli.'inl.  « liil.- cciilnil  <{«[.     Ariiuiid  I  lie  niiicul.ir 

II  ;;i(.li  i>  II  pjilr.  Ill fii-iiy  r((lr\  wliicli  Iom's  ilsclf  in  llic  ;;«lirr.il  Ic.iic 

"if  III.'  riiiiiliis.  hill  jipiMMi-s  (|iiil('  >liiir|)  on  Ihc  inner  side  nl'  ilu'  ovjil 
niMciibr  rciiiiiii.  The  di^(■  i^  ,1  niirriiw,  wliilc  ((v.il,  \vli.i>f  Icn^'lli  i> 
iilidiil  ciiii-lliird  llir  licifilil  .if  III.'  pt-clcn.  A  niinilx'i-  ..I'  .ipiii|ii.' 
ii.i'vt'  lil.r.'^  inn  ii<i'i.>s  Ihc  l.;ick}.'r..iind  iil  i'ij,'lil  aiinlcs  In  Ihc  piipilhi 

■  iiiil   I'ii.lc   iiil.i   Ihc   u'ciici'ill  j.'r.iy   .if  Ihc   I' Ins.     Th.'  pcclcn  iiii>cs 

I'liMii  Ihc  upper  purl  ..f  lli.'  disc,  sprc;id>  .ml  .m  il  liki'  lli.-  r.i.il  .1)'  n 
III'.'  Hiid  H:rii.lii;illy  .li>iippe;irs  inl.i  the  piipilhiry  siilisl.nui'.  l-'ridii 
lliis  r.iol  il  l.iiii.'.  slender,  spinil  f.irni  pr.ijeels  inl.i  Ihc  xilccoiis.  It  is 
lirowii  in  e.il.ir.  is  .if  niiif.irin  wi.llh.  l.i.iks  like  :i  .orkscr.'W  ni\,\ 
e\liii.ls  Inrw.ir.ls  iin.l  .mlwiir.ls  iis  fiir  :is  lli<'  eye  ciin  s.-.'.  liMikinj;  ns 
if  il  weiv  presx'd  ;ij;,iins|  the  l.iw.'r  purl  of  Ihc  li'iis.  Tiic  iinlerior 
.'II. I  .if  I  h.'  peit.'ii  1>  iniieh  .hirker  ill  e.il.ir  llniii  ils  p.islcri.ir  li;ilf. 


Sphenisciformes 

Kl.M  k-l.HilKP)    ('m'|^:i  I'i:\.,i  in.      Sphcni.ii-d.'i  (l,iit(  rxiis.      I'hilc  \I\'. 

'I'll.'  .I.iiiiiiiiinl  col.ir  .if  Ihc  fiindiis  is  l>ri«lil  re.l  sluidinf;  l.i  crini- 
s.Hi.  il  i>  slipplcd  wilh  ininiilc.  ihirk-r.'.l  tin. I  .iriiiiKc  d.ils.  nineli  like 
trniins  .(f  s;ind.     .Mi.ml  ,1  .lisc-lciij,'lh  fr.mi  liic  upper  en. I  .if  the  npli.- 

.lise  these  .h.N  liccmie  yriiyish-wliilc:  iiid I.  Ihc  fiiii<|;d  c.ilonil  i.iii 

i-  di^liiiclly  -r:i.\'  l.iwiirds  Ihc  upper  Iniif  .if  Ihc  cycKrnnnd.  In  ,'i 
icyi.in  III.'  ^Miiie  disl.in.i'  l.iWiirds  Ihc  li'iiiponil  iis|>ec|  of  |hi'  liack- 
ui-oiiiiil  iii:i.\  lie  x'.n  :i  elnslcr  of  piiifi.iiiil.  Iiriiliiinl.  uliile  dots  in  Ihc 
iii.i.iil.ir  iircii.  I'eiii.'iiiiis  nse  Ihc  iiicliiliM^  ni.'inlirMiie  \ery  fre- 
<|ii.'nl!\-  when  liuhl  is  Ihrown  .m  I  his  purl  .if  the  cycijr.iiinil.  The 
optic  .lisc  .'Nliiliiis  I'lijini.'l-whitc  c.ljr.'s;  il  is  hoilow.'.j  out  in  the 
eenlr.'.  iik.'  :i  scwiiifj-iniiehiiic  slinltlc.  Hnnnini;  n.r.iss  this  c.iii- 
iMvily  :in.!  ;it  rifrhl  iiiii;l.'s  to  lh<'  intir^'in  .if  the  .lis.'  .me  sees  .1  iiii'f;e 
niinili.'r  of  ^'niy  Hlircs. 

'I'lic  peeten  lies  .dolifx  the  cciilr.'of  Ihc  iicr\.'.  hIi.i'c  it  is  oi'iinue- 
r.'il  in  col.ir  iiikI  inotlic.l  with  ininnle.  Iir.iwn  pifiin.'iil  .l.ils.  Tlu' 
pi'cteii  li;is  t'le  nsind  diirk  .hocihitc-lirowii  shii.lc.  It  is  of  spinil 
I'.irin.  iik.'  a  c.irkserew  hii.l  .111  ils  side.  .\  few  slcn.lcr  .ipaiinc  nerve 
lilir.'-  are  \isil)|e  on  each  side  of  an.!  al  rifjhl  angles  lo  Ihc  disc. 


I  1,'H 


v::,.'?-;'--:v^' 


CARINATiE 


Ralliformes 


I'l.AiK   XIII  Ariiiiiidcn  li)ic(il/(i 


Spheniscifonnes  Pi.vtk  XIV  Sphml.sru.s  dnmrm^ 


CARINATiE 
Alcifortnes 

l'illl\.      h'nifi  rri:l,i  iirclicii.       I'l.ilr  W. 

'I'hr  lyiuriiiiiiil  is  ml  ;iiii|  nilhcr  iinifuriiily  >li|i|ili'i;  uilli  -.ni.ill. 
liiivr.l  lij;li|.n-.l  iiii.l  .Ii,ik->,'fiiy  dot-  \l„,\r  ||„.  upprr  nid  uf  llir 
Kplic  iliv  .'iiiil  Inwjirils  Ihr  Innponii  •    tr  i^  :i  Miiiill.  khiik!.  ivd  mv.i 

■.iin-diiiiilcd  l.v  .1  palf.  Iii;lil-nrjiy  •llni.  .I1..I   vxjlh  l,ri;.'lil   liiir I  he 

iMiliT  ,'irid  iniiiT  iii;ir«iiiN  douMli'sN  the  iiiiiriihir  iiKimi  willi  iU 
niiind  fr.v.M.  Ili'iid  iiDlici-d  lliiil  rml  uiilv  llii>  twin  l>iil  riin,|  ..f  IIk' 
iip|Mi'  hair.pf  Ihi'  I'liridiis  i^  v.tv  s.iwili\c  In  lii.'|il.  Tlic  ..plii-  p.ipilhi. 
cil'I'iiii;.  iLirriiH  ;iiid  willi  :i  nuiiidid  iippcirvl  icjiiily.  Ii.»  |i,\\  (Inwn  jn 
Ihi'  .y.-iDiilid.  h1i;|i-  IIic  piclcn  cvlriKU  urll  lc.i«,ird  .irid  IhIhihI  lljr 
Inwir  iii:iii;iii  nf  tin-  pupil.  A  \  i.'W  ol'  Ilic  inmli.-.id  i,  rrmcli  nl.- 
sciiic  <l  liy  I  he  Imdy  of  I  In-  riiiis^ivc  pcclcii  wliicli  iilriiiiNl  <-.,\iT-.  il  wlicii 
xiii.  ii>  wilh  III!'  iiiiiriir.  frmii  mIhivc  iIuwiiwm'iI.  Tin-  >riinll  sci.'- 
iiiciil  \isililc  wilh  III,'  iiplillinlriiiiM'op,'  nppcir-.  not  lirilli^iiil  wliil.' 
IhiI    imIIici-  ;i   l.liii>li-wliilc.  Ilir  iM;iii;iiis  cif  I  III'  pclrri  ImIii;,'  I'dvcrrd 

willl    lll.K  k    piiXIIM'lll. 

Kvli'iiiliii;;  ill   i'ii;lil  ;iiii.'li's  In  llir  .Hm-  on  liolh  sides  .iii'  ii  frw  very 

tin,',  yr.iy  np;i,|u,'  ii,'r\ ,'  lilircs  lli.'il   liiiiilly  disiippi'iir  in   ||||.  f |;il 

IM'iiplii'iy.  'I'll,'  pi'cli'ii  is  ,.r  111,'  usnni  (liiM'ipliili'-liniHii  i',>|,>r  mikI 
"■ ''^  "'11  I'liiUMi'd  loHjirds  llii'  lens,  (spiiiiilly  in  i|,  inlViiui-  iispcl. 


Lariformes 

(iliKM-   Hl.M  K-n\<  Ki:n  (Il  I.I..      I.drii.y  DKiriiiii.--.      I'liilc  \\l, 
'rii,'  p'licnil  (olniMlion  nf  Hk'  ,'\,'-.'i'niiii,|  xiirics  fn.in  ii  dull  jiiiiy 
In  11  iliill  lin.un        iiinsily  III,'  l.ili,'!-       I i;i versing  wliicli  jirr  niiiny 
ri'ildisli  i'lini'<ii,|:i|  \,'ss,.|s  running,'  ninii'  nr  |,'ss  in  n  \rrlic:d  din,!  i,in. 

'•  i^  IIk'  Im'i-  iind  \isil.ilily  nf  Ihi's,'  cjipill.irii's  lli.il  ;;i\,'  ih,'  i,,! 

Inn,'  In  iin  I'yi'-jjrniind  csscnliiilly  ixr-.iy. 

Tlic  nplic  ilis,'  is  il  loiii;.  niiiTow  ,.\iil.  ({iiil,'  uliilc.  wilh  ii  ,|iiiin- 
lily  nf  fill,'  f;riiy  lines  riidiiilinj;  in  nil  liire,!  iniis  frnni  lli,'  piipilliiry 
iniii-yin.      On  tli,'  inni-r  :ispee|   nf  the  ,'ye^^rniniil  Hie  niiiiiilii   is  sc'ii. 

Il   is  siliiii|,',|  ill I  nil,.  ,|is('-|erif;lh  frniii  Ihe  iipp,'r  ,'\lr,'niily  ,)f  I  he 

pecten  iin<l  liiilf  11  ,lise-|enHlh  iiKnve  Ihe  ind  nf  III,'  Miine  <>r;;iin 
"II  Ihe  inner  si,].'.  'I'lie  niiiciihi  leseiiilili's  n  lilii,.-i;i',','ri  (hik,'  nf  iri- 
desciit  cjljiss.  It  is  nf  ,,\ii|  shiipe  wilh  ii  reildisli-lirnwn  c'liler. 
which.  linwevi'V.  is  nnprnvided  wilh  11  r,'i;,'\  riii};. 

The  peel, 11  iippi'iiis  In  li,'  in  fnlds;  ih,'  |nw,'r.  or  hrniiiler  pnri  inn 
exleiids  wi'll  forwiird  lowiinls  Ihe  ji'Hs  i.nd  liiriis  lowiirds  Ihe  iiiisid 
side  nf  III,'  liiriTs  liciiil.  The  inner  ((Uiidiiinls  of  (h,.  fmiilns  iir,'  more 
eiisily  s,'en  wilh  Ihe  ,>plilliiilriinsenp<'  Ihiui  ih,'  nii|,.r  jmir  |,ii|,  so  fur  iis 
Ihe  hiller  iin'ii  is  visiMe.  ther,'  is  nn  si;;ii  nf  i,  sc'on.l  niiieiihi  on  Ihe 
nnli'r  piirl  nf  Ihe  eyi';,'rnnnd. 


!  I^+  I 


CARINATiE 


Alciformes 


Tlatk  XV 


Frail  rriila  arrllcii 


Larifonnes 


Plate  XVI 


Lan. 


U.1  marinua 


CARINATiC 

Charadriiformes 

SrovK    ri.iivm.      tHiliriiiiHii.s.milojiii.i.      I'hih'WII. 

I'l .M'UiiiiiMcl   i«   icildisii-l.ri'HM.  nillii  r  iliTpIv  iii^'tiiriilcil   iiriir 

I  III   |«ri|iliin  HMil  (iivcnil  hIMi  iininp'-ri'il  i|i>N  lliiil  nri'  mt\  (Iriix'ly 

|KM  kid  ..II  till'  ii|i|Hr  linir  ..f  III.'  f |ii».      |<<'li>»   III,'  i(|«l',c  I'litriiiK'i' 

iirr  iiiiiiiin.il,  ilinriiiihil  \r,>.|s  riiiiiiiii^'  piir.ill.l  ulth  jiiil  oti  <.jl|irr 
-illr  .if  (111  |M|illl.i.  Tllr  lll;i(  lilii  i,  mil  ijinlly  .l.tihr.l.  ||  i,  >iti|,i|r<l 
llli-.M'  llli-  ..IIIMTinr  I'Mil  i.r  lllr  iliM'  oil  In  I'lilKT  or  ll;l>.ll  >i.|r.  iiliij 
nliiiiil   liiill'  ihr  ii|>|).'iri'iil   liiii-lli  iif  llii'  iMcliii  friilii  llir  ii|>|h'|'  riiij. 

Till'  riiiiilii,  iiiliiiiiiy  is>lif.'lill.v  iliirkcr  in  Ilir  rii^inihir  .irr.i,  wliicli 
is  siiriiiiiiiiji-.j  l.v  ;i  r«flc\  riii«.  piili'  ur.iy  in  mlnr.  in  I  lie  fi.rin  iif 
v«T\  iiiiniilc  lines  nnlijilirn;  frnin  iU  iiiiir«in>.  Tlirrr  iiri',  iilsn,  ti  few 
r.iiliiili.iii,  iifiir  llir  f..M;i  (■rnlrjili-.  Tlir  p.'ipilhi  i,  .villi,-.  n\iil  in 
sli.i|M'.  frinm-l  :ill  ninnil  willi  (Iciisc  l>l;i(k  pimiiinl.  ninl  ii  few  «riiy, 
iip.ii|ili'  iii'iM-  lilirrs  iirr  mtii  mi  lilliii-  siij..  i,f  j|.  'ri,,.  prclin  is  \rr\ 
hiix"'  mill  |(nijr(!s  well  inlo  llir  \il  irons.  ||  is  ,,(  nnnsiiiil  sjuip,-. 
nil  her  ii;i|io\\.  Iiiil  whin  iN.iiiiinril  rroni  jilmvf  looks  :is  if  il  Iniii  Imtii 
''""i|"''' I  .iMil  Ikilliiiiil  on  liolh  siilr,.  »il||  il  !i:iiiin\  nlci'  :ilio\c. 


\>ii 


Gruiformes 

Km. I.      Illii.    lilt  Ins  jiiliiiliis.      I'liilr  Will. 

Till-  li,i(ki,'i"nn<l  is  ciivcrrd  wilh  ji  niiiss  of  iiiiiiiilr  ilols  IJuil  nrc 
!.'i;i.>  in  III.,  iipp.!'  Iiiilf  of  111.-  fiin.liis  iiriil  oriiiij.'.-  li.L.w.  Th.-  !.,«,. r 
s.-iloi-s  of  III,,  fiiiiiliis  iir.-  slippl,.,!  uiili  pi^rni.-nl.  Cli.ir.ii.iiil  v.->s.-|, 
ill-.-  iiiiiii.roiis  Mini  mil  in  nitli.r  s|r,iii;|i|.  v.-rli<iil  liii.-s  on  ImiIIi  si.|,-s 
of  III.-  .ipli.'  .lis.-,  'rii.y  iir.-  .lull  oriiii;;.-  in  color.  Til.  fov.-;i  is 
shown  l.iHiiiils  I  hi'  iinl.rior  or  n.is;il  hjijf  .  ,  ii,  i.  ;iiii|  jipii.-.irs 

"^  -I  ' ml  hill.'  or  .  Tiil.r-liki'  il.'pr.'ssion,  luin, ..  in  c.ilor.  which  ii'- 

ll.'cls  .'I  i;i'iiyi>|i  ,|„'.'ii  fi'..iii  ils  c.'nli('.  \  narrow  (.'i-iiy  .ir.l.-  ..r  rcfl.'X 
rin;;  siirr.iiin.ls  I  his  pi|. 

'I'll.'  oplic  .lis.'  hiis  ils  .'.'nln:!  p.iilion  iippiir.nlly  slippl-.j  wilh 
l>rii;hl  orinm.'-rc.l  ilols,  wliil.'  ils  niiir>,'in  is  friiiK.'.l  wilh  ..liirsi'.  wliil.' 
(ilir.'s.  IhnI  jirc  iilso  slinj.lcii  wilh  lirowii  pijiiucMl  .loN,  ispcciiilly  n.'.ir 
I  he  .lUliT  lior.l.'r. 

'I'll.'  p.'.'l.-ii   is  of  ih,.  iisiiiii.  .||...p  (■|i..co|iil.'-lii'own  I'oior.  riilhir 

iiiirrow  wh.-r.'  il  j.iiiis  lli<>  .jisc  Iml  licconiiii),'  mncli  llii.'k.r  .iii.l  n- 

niiissi,.-  ils  il  pr.ij.-cls  inl.i  I  he  vilr.-.nis  lowiir.ls  I  he  l.-ns. 


I  I. '11! 


^H:^^^^fSii 


•■\:.~^i 


1^:     "^t5^>^-i'£<vi  A^''^ '  '^:^'MiM 


CARINATiE 


Charadriiformes 


I'l.xih;   W'll  iV.ilicniiiniK  urdliiinij 


Gruiformes 


Platk  XVIII  Rhinoclicliix  julmliix 


CARINATiG 
Gruiformes 

Hll\/ll.l\\    SkkikMV.      I  iin,im,i  rri.'iliilii.      I'liili\|\. 
■|"lir  <l<>riiiii,'iiit  color  of  III.-  riiiKJiK  iMiili  is  »  iliill  .{nil..     Omt  \\w 

'""'■''    "("'"''■iinls    of    II y.Kroiin.l    run    nillur    »lnii>;lil.    (Iiill-ri-<l. 

rlior.ii.liil  inpilhirirs  lli^it  f,„|,.  „„„y  „,  ||„.y  n-iicli  llir  ii|>|h  r  l.;iir 
i.f  Ihrfi.-I.l.  This  ri'Kionisiilsosliol  wilh  a  «r>'<'iii«lililMr.  miishii  likr 
film,  vxlii.li  i»|.rol.;iliK  M  r.'lliTli..ii  1>\  I  he  ntiiiii  of  liylii  ni.vs  friHii  Ihr 

o|>lilliHlllln.<'o|>ir    fl.irn.r.       Al.ovr    III.-    .'ImI    of    III.-    ,|is,.    1,    , ,,||. 

roiiiiil  <li|.r.Nsioii.  •|tiil<'  rl.Mr  of  ,iti\    rr(l.\.      To  Ihi-  iiiiicr  or  liciik 

-icl.'  of  llir  eve  is  t|ir  cirniliir  Illiiciilii.  «  liosr  ijiiiliii'li'r  is  .iImiiiI    IIii 

liiii.'s   llinl    of  III,,  iiivily  ill    IIkm'IIiI  of  III.,  .lis,-.      T|„-,,.|ili-,'  .if  lli.- 

liii-u.r  .  ii-.-l.-  is  .|iiil..  ,.|,.|,r.  Hill,  ||„.  ,.v,-,.|,|i f  i,  l.rjyiii   ,||j,||, ,„.,.. 

siiili   ^is   is  soni.-li s  s.-,ii    ilioiii    ||„.   Iiiiinnii   fov..|i.      Tl,..  .  ir.-iiin- 

f.-nii..-  of  lliis  .ml.'  is  ,|iiir|,|y  .l.-tiii.-.l.  .,n,\  |,„,  „  |,rii;||i  riii^  iiroiin.j 

il    .>f   t'lish-llill!,'    «|lil.-,        T|„.   ,,|,|j,.   ,|j„,   „|,|„.,,,.,   ,1,   ,1    |,,„j,    „||j,,,   ,,^.|| 

uilli  irr.-«ii!iir  iiMri:iiis.  Tli,'  l)l,-i,-k-l.roHM  ,-..rrim:il.  ,|  p.-.-i.-i,  i, 
v.-i-y  hii-i;.-  iiii.l  loiii;:  il  ,.\l.-ii.|,  into  lli,-  vilr.-oiis  .-iikI  ;ili,ios|   l..,i.-|i,.s 

III.-    Iciis    uilli    il,   ,-liil,-s|ii,|».,|    l.-rniiiiiil.      \.i-y    fi ,,,„,i|,.    ,„.rv,. 

tilircs  ni.li,,!.-  ;i|  i-.-n:iiliir  inl.-rviils  from  Ih.-  »||,,|.-  |,„|>illiiry  ,-ii-<iiiii- 
fi-rcii,-,.. 


n 


Ardeiformes 

l-!i  imi'KW  \i(.irr  IIkii>i\.      Xi/clinirii.r  ni/rlii-nni.r.      I'liil.-  W. 

Th.- i-\.-tfi-.iiiiiil  is  .lull  -niy  IIII, I  .■ov,-i-,-,l  will,  ymv  isli-nliii,.  ,|,,k. 
Th.-  ioH.T  pi.rl  of  III.-  ftiii,|ii>  .-xhiliii,  ;,  iiiiiiil„.r  of  .|i|||.,-,.,|  ,.  i,,roi.liil 
M-ss.-|s.  i|i;,|  rii  1  ill  ;i  \,-rli<-iil  ,lir,'<tioii. 

Tli.-o|ili.-.li.,-  is  li>ii;,' 1111,1  of  iii,.,|iiiiii  «i,||||,  will,  ImiIIi  .-\li-.-iiiiii.-, 
romi.l,-,!.  lis  ciilr,-  is  .,n,ii>;.-r,-,|  hiiiI  ,.,\.-r.-.l  will,  ininiil.-.  lirowii 
|iii;iM.iil  ,l,.ls.  Til,-  |i,-,'|,'ii  i,  ,|,>,.|i  |,r,,\,ii  iiiiil  ils  oulliij,-,  „,■,■  «,.)| 
<l,-tiii,-,|  III,-  »li,.|,-  l,-iijr||i  of  III,.  |i,i|,i||„.  |,ii„.,ir.  yi-iiyi-li  r,-i, Mill  ions 
'■\l.-iiil  from  111..  ii|>|i..r  IvM.-lliir.ls  .>f  lli,-  opii,-  .iilriiii. .-, 

Till-  >.,ii,-iilii  is  siliiiii.-,!  ,|iiil,.  ,-l,>s,.  1,1  iiiiii  lowiir,ls  ih,.  ii|i|i,.r- 
iiiisiii  iis|,,-,-|  of  III,.  iiis(-.  Il  is  siirroiin.l.il  \,\  m,  oiil,.r  riii};  of  wliilish 
liiKs.  lowiirils  wlios,.  ,.,.|iir,.  is  ii  /oiu-  lliiil  i-loscly  r.-s.-mM,.,  ||„.  mii-- 
roiiiHliiiK  nliiiii.  Ill  ils  ,.xii(.|  <-,.iilr,..  iiKiiiii.  is  ii  siiiiill  fov,.ii  ,-oiii- 
|ios..,|  of  >;riiy-\vlii(,.  slriir. 


■f'  '''■■'■T-, 


1 1;>8 1 


/-*  ■  ,=3Mi"«!''Wr«3J« 


II I  mm 11    iiiiiiMiii  iniiiiwiyiniiMiin 


CARINATiG 


Gruiformes 


I'l.MI     \l\ 


'  (iriiiiiiii  rrixliilii 


Ardeifonnes 


Pl.ATK   XX  yi/cHniraj-  nijrlin 


^r    .    . /.l 


CARINATyE 
Ardeiformes 

KlIIOI'KVN    UlTIKUN.       lillllllinis  .■ilillllrix.        riiitc  \XI. 

Th.'  <'yc).'n.iin<l.  riioslly  riKiiiM-colorcl  sli.i.liiiK  In  v.-llow.  is 
spririklr.l  Willi  Miijill.  <lull-\vliilc  <|„|.s.  AIiiionI  iiriinr<lijih.k  i,l„,v.> 
I  he  upper  riid  of  llir  opiic  lu-rvc  <'iitrim(<-  iiiiil  l.wir.ls  tin'  ii;isiil 
si.lr  .)f  tlu'  .lis,-  is  llic  iimciilar  iircji.  Tlic  fiiiidal  <l..ls  iil  lliis  point 
lire  iniicli  .liillcr  in  li.iif  inul  incline  I, .wards  a  iliill  luitf  (•..l..r.  The 
rejiion  of  llie  macula,  enclos.',!  I.--  two  <ircles.  cine  within  the  .illier. 
is  also  chara<lerizc.l  l.y  Ih.'  pr<  sene<-  ..f  v.-ry  short.  I.rijrht.  hluish- 
Kreeii  lini's  radialiiifi  from  the  centre  of  the  fovea. 

The  optic  (jis<'  is  ovoi.l.  Iihuit  at  its  up|)er  extr.'Uiily.  and  app<'ars 
as  if  its  loMKcr  margins  descrilie  a  series  of  small  curves  correspond- 
wvj.  lo  the  folds  of  the  peclen.  The  disc  on  either  side  of  the  root  of 
the  peel  en  is  dull-hrown;  near  l.y  are  small,  oratig'e-ri'd  choroidal 
capillaries.  The  papillary  marjiins  are  <|uite  white  and.  in  contrast 
with  the  shadow  cast  upon  the  neij;hl.orinf;  field  l.y  th<'  dark  pecten, 
the  dis<-  slan<ls  out  iir  sharj)  contour.  KxlendiuK  a  short  dislan<e 
ove  the  fundi  and  alioul  the  optic  disc  are  a  few  opacjue  nerve  fil.rcs. 
The  iH-clen.  convoluted,  wit!-  s<Tratcd  mari;ins.  and  of  the  usual 
cli..colale-l.rown<oh.r.  extends  l.ch,w  the  lower  end  of  Ihc  opt  i<<lisc. 

HoAT-HM.i.Kii  Xk.iit  Hkhon.  Caiicromn  vocliliarla.  IMale  X.XII. 
The  eycKrouiid  is  <lull-r<'<l  and  <<.vcred  with  (.range-red  dots. 
These  punctate  dcp..sits  are  intermixed  (.n  the  upper  half  of  the 
fundus  with  snudh'r  ami  l.rij;liler  .lots  of  a  grayer  l<.ne.  (t.i  the 
l"w<r  half  and  <.n  each  si.lc  of  th.'  opti.'  n.'rvi'  are  a  few  ..range-red 
clior..i<hd  vessels,  that  rmi  in  a  v.rti.'al  .lirecti..n.  parall.l  t'i.  the 
long  axis  ..f  the  .lisc.  Th.'  nia.ula  is  situated  le.war.is  llie  misal  si.lc 
..f  th.-  ii.rvc  hca.l.  This  sensitive  area  is  rather  l.rightcr  in  c.h.r 
than  th.'  surr..unding  fi.'M.  an.l  several  white  .l..ts  ar.-  inchi.l.-.l  in  it. 
Tins.'  small  d.ils.  Ii..wevcr.  arc  notic.-al.l.'  only  wh.'ii  th.'  light  ..f  th.> 
mirr..r  is  r.-(l.-cl.'d  on  the  r.'gi..n  in  certain  .lire.tions.  Rather  a 
l.right.  irregular  an.l  linear  rcfh-x  surr.iun.ls  th.'  macular  r.'gion, 
which  is  v.ry  scnsitiv.'  1..  light.  Th.'r.-  is  a  h.ng.  narrow  papilla  with 
roun.h'd  .■xtr.'miti.'s.  It  apjM'ars  as  if  it  were  c..mp..s,'.l  .,f  sh..rt. 
whit,'  fil,r..s.  surrouM.ling  an  orange-red  centre  c.v.'r.'.i  with  nnmit.'. 
<lark-l.rown  pigment  grains  that  f..rm  a  Mctw..rk  ..v.r  th.'  wlu.h-  r<'d 
an-a.  Kxten.ling  fr.ini  .'a.h  si.].'  .,f  the  .lisc  across  the  retina  an-  a 
few   dull-gray.  opa<|iie  ncr\c  fil.res. 

Th.'  p.'.ten  can  I..'  trace.l  th.'  wh.ih'  h-ngth  of  the  .lisc;  it  is  .lark 
l.rown  in  .'oloi  an.l  gr....ve.l  spirally  like  a  corkscrew.  It  .I.m's  ii..t 
appear  t.)  ...m.' far  f..rwar<l  t..war.|s  th.' l.-ns,  an.l  its  uni.m  with  th.' 
n.-rx-.'  hca.l  can  r.'a.lilv  l.e  Irac.-.!. 


14U! 


CARINATiE 


Ardeiformes 


Platk  XXI 


lidUuiriix  xlilliirix 


Ardeiformes 


1*1, \TE  XXII  Cniicroma  corhlcaria 


CARINATiE 
Ardeiformes 

<;r,()s.sv  Ims.  Pln,mlisf„lrii„lh,.i.  I'ljitc  Will. 
Tl„.  „,,u.ral  ,ol.,r  of  ll„.  .-.v.-Kro,,...!  i.s  l.lu.-^-rav.  It  is  ....v,.,-,..! 
.,v  a  .,>a.ss  of  niiMut.-.  ^aavisli  ,|o(s.  Ihnl  prol.al.ly  f„rnisl,..s  |(,,.  |,V|„ 
I...  .r.  Inn.l  kh.v  ..,„..  .1,.,  a,,,K.ars  wh.n  ll,..  rays  r,.(l..,.t,..|  |,v  ||,.. 
..|.l.  l.alnu.s,.o,H.  ar,.  throw,.  o„  ii.  Tlu-  i„f..rior  .,Ma,lra.,ls  ,',(  ||„. 
r.ni.lus.  ,„,i...bMK  Ix.ll.  ...ar^nns  of  ll„.  opli,-  ,|j.s,..  ,.x|,il,i,  ,,  |,,,.,,. 
"un.  ,..r  of  oranK..-r...l  ,.|,oroi,lal  <.a|,illari..s.  Tl.,.v  ar,-  v,tv  mummt- 
""s  Im-Iovv  ||».  n..rv..-l,..a.l.  an.l  s„tr„s..  ,|„.  „.|,ol,.  f„„.|„s'„.ar  ll,,- 
I«Ti|)licrv  with  an  oraiiKr-|)iiik  kIi'W. 

.\|,,,ar,.iilly  Ih.-rr  is  I.mI  o,„.  ,„i„Mlar  ar,-a.  situat.-.l  al.ov,-  thr  .lisc 
an.l  on  .ts  nasal  si.h..     In  th,-  .rntr,.  of  this  r.-«ion  is  a  small,  whit... 
■•..nn,    ,h,|    s„rroun.l..l  l.y  a  hrilliant  l.ln,.-Kr..,-n  rHh-x.     Th.-r,.  ar,- 
also,  iuw  Mm-s  ra,liatin>;  from  tli,-  <vntr,-  of  th,-  f,>v,-a 

Th,.  papilh,  s,-,.ni.s  to  1„.  forn>,-,l  of  ;,  mass  of  ,■„;„,,•.  «hii,.  fi|,r,.s 
'  '•■•'■'  •«■  l«a,-.-,l  for  al.„ut  half  its  l,.n«lh  only,  th,-  low,-r  part  U-inK 
...M-nr,.,l  l,v  t  ...  n.a.ssiv...  .-lnl.-sha,H-,l  p.-,,..,..  Th,-  lall,-r  or^an" 
"f  III.-  ..s„al  ,h,.,„lat,.-l.rown  ,„h.r.  proj,-<-ts  w,.||  forwar,!  t,.»ar,ls 
IIh-  po..l.-nor  as,K-,-t  of  tl.,-  K-ns.  Tlu-  ,lis,-  is  l.or,|,-,.,.,|  ,vith  l.h.,-k 
p.Knu-nt  wh„.h  ,-,-s,-ml,l,.s  a  sl,a,l.,w  ,-ast  on  ll„-  ,-y,-Kro.,n,l.  A  larK- 
>""nl„-r  of  s,.nn-lransln,-,-nt   n,-rv.-  fil,„-s  oripnal,-  at    (h,-  ,.,l„,.s  of 

""■  ';"";;  '"■;" ""  ^"l'-^-  '•^l'-"«l  "<t..ss  tl,.-  ,h..roi.lal  v.-ss,-ls  a.„l 

,-v,-ntiially  ,lisapiH'ar. 

Vmkimcan  J.'.Mim  .      Mi/rlrria  aiiirrinni'i.      I'lat,-  XXIV. 
n,,-  K..n,.ral  ,-oh,r  of  th,-  f,.„,|„s  is  „  slatc-grav.  th.-  wliol,-  .-v,-- 
«n,un,l  l.,-,nK  ,,ni|,.  nnifomiiy  sprinkl,.,l  with  small,  Imt   varion'slv 
S.Z.-.I  whit,.  .lots.     In  ,h,-  npp,-r  an.l  nasal  ,,na,lrant  of  tl„-  pi,.|„r,;  i"s 
lli<-  small.  sinKi,.  ma,-nla.  an  ar,-a  ,lark,-r  than  th,-  snrr.-nn.lin,;  parts 
wh..s,-  .-xa.t  ......tr,-  is  o,.,.npi,-,l  l.y  ,h,-  fov,-,.      I„  ,|„.  h,„,,.  t  wo-thir,ls 

"I  II.,-  fi,-hl  an-  s.-,-,.  nn..u-r,...s,  plainly  mark,-.!  ,-h..r..i.ial  v.-ss.-ls  that 
-xt.-n.l  th.-  who!.-  h-r.fitl.  of  th.-  p,-,-t,-n.  .-onn-rKinK  s,m>,-what  towar.ls 
II"'  |...sl.-rior  asp,.,.,  of  i,s  has.-.     Al.ont  tw„.thir.ls  of  H,,-  lon«  an.l 

,:\''  '"■"""'  '"•'•^•''•' '  '^  l''""'l.v  visil.h..  ,.x,.,.p,  ,h,.  ,.,.,.,ral  portion 

whuh  ,s  part  .V  ol.s,.,.,.,.,|  l.y  ,|„.  ,,,,„.,,  This  larK,..  l.ia..k-l,rown" 
OVUM,.  ,hv„l,.,|  mto  1.5  lai-K,.  a..,l  s,.v,.ral  nn«h  s.nall.-r  ,lonl,|,.  fohls 
'';>"in,at,.s  al,ov,.  in  n  thin,  .lark  r.«|.  Th..  .lis,-  is  fiinK,',!  I.v  ,h.rk 
|..«.n..r,t  «ra,ns  an.!  fron,  its  lat..ral  .nar^iris  pr-oj,.,.,  .  „„„;,,,,  „f 
sh,.rl.  faint,  whitish  lin,.s. 


Hi] 


'm,'k 


^:^.' 


CARINATiE 


Ardeiformes 


Pi-ATK  XXni  I'lnjadl,  faliincUun 


Ardeiformes 


Pl-ATK   XXrV  Mijrtin'a  aiiir 


CAMNATiE 

Ardeiformes 

Si'dOMill.l..      I'ldhilid  liiiciiriidid.       I'lalc  \X\". 

'rill'  ccpIiii-  111'  till'  cyrjiiiiiirKl  is  (Icciiii'illy  ;.'rjiy,  lit'ciiiniiiK  lirnwiiisli 
lii\viiril>  Ihi'  |irri|)li<'iy.  Tlir  nilirf  fimiliis  i>  cnvcrcd  willi  iniiiiilc. 
iiTfiiuliiily  >li:i|«'il.  uiiiy-wlillr  ilols.  Ili^il  ii|i|HMr  iiiiirc  (lisliiicl  iilioiil 
llif  iii;i('iihir  rt'jjioii.  At  I  lie  I'ovcii.  wlicri'  llu'y  iirc  lirillitinl  wliilc, 
llicy  iiir  >lill  iiiiiri'  cloM-ly  |iii('ki'il.  'I'lir  fiivriil  ri'f;ii)ri  iippciirs  lit  lie 
Miiikcii  Ih'Iiiw  its  Mirnpuniliiii;s  iiiiil  u>  lir  riicltiscd  in  ii  pale.  ;;rci'iiisli 
in'llcxi  riiij;  that  is  nf  oval  slia|M-.  with  its  loii^  axis  hori/oiital.  The 
optic  disc  is  a  liiii},'.  narrow  oval,  and  presents  a  lirilliant  white 
ap|M-aranec.  Near  its  upper  end  arc  several  choroidal  vessels  of  a 
pale.  v;"hlen-yellow  color.  Parallel  to  the  loni,'  axis  of  the  ner\c- 
hcail  is  another  eloiiyati'd  mass  of  white  tilircs  lahnosl  like  a  second 
optic  disci  having.'  its  centre  stippled  with  fine  pi<;nient  dots,  and 
cxlcndint;  across  the  eye;;ronnd.  Hadiatinf,'  from  tin  marj,'ins  of 
the  papilla  one  sees  a  nnmher  of  faint,  translucent  titires  crossinj; 
till'  small  white  area  on  the  nasal  side  of  the  nerve. 

The  pecteii  diK-s  not  extend  very  far  forward:  it  is  dark  f;ray- 
hrown  and  appears  to  l)e  completely  covered  » ll  h  a  nuinlier  of  warty 
prill  iil)erMiices.  It  ap|K-ars  to  lie  attached  to  the  whole  len;,'th  of  the 
centre  of  the  disc,  that  is  stippled  with  tine  red  dots. 

Anseriformes 

Hi.M  K-Hi:i.i,ii;i(  Tni;i:  I)i  ik.    Ih  iHlriH-iitiuti  iiiitiimiiiilis.    IMatc  WVI. 

The  eye;;roinid  is  colored  a  li;rht  fawn  hesprinklcd  with  minute, 
white  dots,  that  jilistcTi  when  a  strong;  lijriil  from  the  mirror  is  thrown 
upon  them.  ( )ii  each  side  of  the  papilla  is  seen  a  mimlicr  of  choroidal 
\essels.  Iiriirht  oranf;e  in  color  and  rather  strai;;ht.  The  disc  is  also 
oran^e-rcd  alon;;  its  imijor  a\i>.  this  central  zone  hcinj;  stippled  all 
over  with  a  network  of  fine  lilack  dots.  The  circumfcrcnc<'  of  tiie 
disc  is  friTimd  with  while  tilircs.  Ttie  dark-lirown  pectcri  arises,  as 
Usual,  frniii  the  whole  lcn<;lh  of  tin-  disc.  X'icwed  from  ahove  it 
seems  ver>  thin  and  twisted  like  a  corkscrew.  \  few  opaijue  nerve 
tilircs  extend  for  a  short  dislance  and  at  riuht  an>;les  to  tile  disc  on 
ell  her  side.  The  upper  p.irl  of  the  fundus  is  almost  oliscured  liy 
iiuiiierous  minute,  lirilliant,  while  dots. 


mi 


m,..M  .mA-:i\\m  ..jl"  -'^jm^^Wf.^..j^,^^mm-.^ 


:  ifWUt  iSisTJXlf: 


CARINATJE 


Ardeiformes 


PUATF.    XXV 


I'lafaliu  Iciirorodia 


Anseriformes 


Platk  XXVI       DciKlriiri/iina  aiitiiiiiiKilin 


m^^n 


CARINATiE 
Anseriformes 

Ml. I  K  Sm)\\-(;i»)sk.      Chni  rtiriilixnns.      I'liilc  \\\||. 

Tlir  fiiiKliil  <nl(ir  is  ii  ilisliiict  fiiwii.  spriiiklnl  with  •.iiiiill.  roiiiiil. 
<iniiii;i-|iifik  (li.ls  iif  irrcKiiliir  sliiipc  hikI  size,  liiiiiiiiriu  vcrl  iciillv 
|>.isl  .'iikI  ixinillcl  with  thi-  optic  piipilhi.  over  tin-  lower  half  of  thi- 
liiiiihis  iirc  iimiici'oiis.  strainlil  orjiiiKr-rril  choroichil  (■■•ipiniiiii's. 

'I'hr  fovi'ii  is  proliiiliK  in<li('iit<'<l  l.y  ji  snuill.  KHsl.iiiriK  white  <hit 
iil>o\c  the  end  of  the  disc  on  the  iiiisiil  side. 

The  optic  iieiv<>  head  is  lioat-sliaped,  tinted  oralij."'  aloiiji  its 
central  zmie.  and  shows  a  narrow  rim  of  coarse  opaifne  nerve  fihres 
that   form  a   frint;e  aliout   its  circnniference.     This  orange  centre  is 

sprinkled    with    nnnierons    minnle.    dark-lirow •    Mack   dots.     \ 

few  Kia.v  opatpie  nerve  fil.res  arise  from  tile  disc  margins  and  cross 
the  fnndns  horizontallv.  The  peclen.  of  corkscrew  shape,  rnns  the 
whole  lcnf;th  of  the  disc  and  comes  well  into  the  vitreous. 


Pelecaniformes 
<'<)UMi)H\\r.      l'liiihiiriHimi.r  varbo.      I'jnte  XXVIII. 

The  fnndns  oculi  is  mostly  of  a  slate-gray  color,  uniformly 
sprinkh'd  with  numcrons.  inimile  while  ihits.  closely  pack<>d  together. 
Rnnninj;  chiefly  parallel  with  the  long  axis  of  the  optic  disc  are 
scver.d  rather  straight,  iirange-red  choroidal  capillaries,  that  extend 
the  whole  length  of  the  papilla  and  l)cyond  its  inferior  extremity. 

The  rnacniar  area  is  se<-ii  a  little  ahove  the  npp<T  end  of  the 
optic  disc  and  on  the  na^;lll  side  of  the  nerve.  The  fovea  appears 
as  a  reth'X  image  of  a  few  short,  hright.  white  lines  snrronnd<-<l  l.y  a 
narrow   ring. 

The  opti<>  disc  ,ip|M>ars  as  if  it  were  composted  of  a  mass  of  very 
while.  eotlon-lik<-  lihn's,  disposed  as  a  fringe  all  aliont  the  papillary 
margin.  The  central  area  of  the  disc.  es|M'cially  on  each  side  <if 
the  root  of  the  peclen  is  orange-re<l.  stippled  with  nuimte.  I.rown 
pigment  grains.  l'er|H'ndienlar  to  the  papillary  nnirgins  are  a  few 
sh.  rl,  tine  opatjue  nerve  fil.res.  that  rmr  h.wards  and  arc  finally  h.sl 
in  the  |H'riplieral  eyegronnd. 

The  iM'clen  is  r.ither  long  and  of  the  nsnal  chocolate  color;  it  is 
innch  narrower  than  nsnal  <.n  the  npp.'r  half  of  the  disc,  and  comes 
well  forward  into  the  vitreous  linnK.r.  extending  liehind  Ihe  margin 
of  Ihe  pupil. 


I4.i  i 


CARINATiE 


Anseriformes 


Pl.ATK   \.W;i  Clnii  arnilfxcniK 


I'l.ATK  XWIII  I'halarrocoriu-  cirho 


CARINATiG 
Pelecaniformes 

(iwVKT.       Sllld  hllx.idlKI.        I'lillc  WIN. 

'I'lir  ;.'i'ii<Tiil  I'tilor  of  I  In-  ('V<>);riHiiiil  is  iliill  vrlliiw  xvilli  ii  ;;rii,\' 
liiil.  I'ViTV  wlicri'  coMTi'd  willi  liulil  «>■">■  'lols,  lli:il  iirc  iiii»l  niiiiirr- 
i>ii«  (III  ilif  ii|)|M-r  liiilf  iif  llif  fiiiKlus,     Kcliiw.  iiiiil  on  riK'li  >iil<'  of 

I  lie  oplir  lU'r\r,  art-  scvcriil  oriinjic-rrd  rlioroidiil   \f>.srl>.  tliiil    lire 
riiirly  slnii;;!)!  ;iii<l  run  |iiiriilli'l  wilii  llir  loii^'  ii\U  of  llii'  disc. 

rill'  iici'M'  crili'MiKi'  iitid  iH'clrii  nrr  siliialcd  I'iillii'i'  liiirli  up  in 
llir  tit'ld:  t'oiisiMinciil  l\'  il  is  t'lisv  In  cMiiniiit'  llic  details  of  llir  |H'ri- 
papillarv    liack^roiind. 

Aliovc  llif  iip|MT  <-nd  of  tlic  optic  disc  and  a  little  towards  llie 
nasal  side,  is  a  small  circniar  macular  ari'a.  red  in  tone  Iml  surrounded 
l>v  a  larv'er  circle,  like  a  n^ay  shadow.  The  niarjlins  of  the  latter 
uradnallv  fade  into  the  liackKround.  The  visilile  mar^'ins  of  the 
papilla,  apparently  composed  of  coarse,  while.  opa(|Ue  til>r<'s.  arc 
iiol.  as  in  many  s|)ecies.  covered  l>y  the  |H'clen.  The  central  part, 
ni'ar  the  root  of  the  |M'elen.  is  orange-red  in  color. 

The  iK'cten  itself  is  evidently  attached  to  tlie  disc  fiu'  nearly  its 
entire  Iriiijlh.  and  it  d<K's  not  come  forward  towards  the  lens. 

.Vl  vritAT.r  w    I'ki.KAN.      I'iIiviiiiii.'<  nmnpiiUldliix.      Plate  \XX. 

The  color  of  the  eyejjronnd  is  a  ihill  liiil  deep  UTax.  sprinkled 
;,'enerally  with  irregular  dots  that  are  most  numerous  in  the  upper 
part  of  the  fundus.  The  lower  <|inidranls  of  the  field  are  covered  with 
a  rather  faint  orany-red.  choroidal  capillary  system,  disposed  in  a 
\'ertical  dirolion.  The  disc  is  a  wide,  pointed  o\'al,  cxhiliitiiiK  a 
mniilier  of  lirif;ht-red  orange  rid;,'es  that  are  uiiiforml.\  stippled  with 
M.ick  pifiuicnl  dots.  The  disc  mar^'ins  stand  out  as  a  clear  while. 
The  pecten.  hroad  and  massive,  seems  to  fill  the  pupillary  area.  It 
proj<'cts  far  into  thi'  vitreous,  reacliinj;.  indeed,  the  post<'rior  surface 
of  the  lens.  In  spile  of  its  lar^'e  si/e  and  intraocular  disposition  itotli 
the  free  ami  the  attached  ends  of  the  pe<ten  can  he  <iullined  li,v  the 
ophtlialnioscope.  Passing;  in  a  radical  direction  from  its  circurn- 
ference  is  a  numlier  of  opa<|Ui'  nerve  tihres. 

The  siii;;le  macula  is  to  lie  found  on  the  inner  side  of  the  fundus. 

II  is  surroundetl  hy  a  mirrow.  sharply  defineil.  reflex  rinj;  of  ;;reenish 
color. 


I  UNI 


^Rf! 


CARINATJE 


Pelecaniformes 


Pl.AlK  XXIX 


.S'm/(»  hanKdna 


Pelecanifonnes 


Platk  XXX        Pelecaiiu.1  conKpicillatiis 


CARINAT>E 
Serpentariiformes 

Sfim.lMi^     lillili.      (iit/iiHii  id/f       lit    Sir/iiiiliiriiii    siriiiiiUiriii.i. 

I'l \\\l. 

'I'lir  u'l'lirral  roll  II'  iif  I  III'  i',\  cui'iiiiilil  j^  itllll  i.'l'>i.\  .  |iillril  willi  nil  veil 
liulit  :iiii|  ihii'k  lii'iiwii  |iiuiiii'iil  uniiii*  or  lllll^.  llir  ihirkir  Ih'Jii;,' iiImiiiI 
iliilllilc  llir  »i/i'  nf  IIh'  linhliT  L'nilllllc^.  Mixci'  willi  IIii'm'  i|iiI>  j,  ,i 
lIclIT  lllii-.-.  nf  mi  MM  1 1'.  Iiriulll  (HiillN  I  ll;ll  in'  it  I  Iii'  u  linlr  Til  In  I  lis.  lull 
llir,\  cull  U'  iilcri'vcil  iIlK  « lii'ii  llic  rflli'i-li'cl  liylil  nf  I  lir  iiiiiriir  i- 
liirciwii  nil  llirlii.  'I'lii'-x'  il('|M>«iU  yivc  I  lii'  lijirkmniiiiil  llir  nplM'iir- 
iimr  III'  ,1  I'li'i^li  >iii'f;i(i',  A  I  hill  hi.M'i'  cif  Iniii-liirnil  iiiI'M'  (iliro 
■•iirroiiiiiU  I  III'  |:'i|iilLi  fur  it  slmrl  ili^lMiiri'.  |iiirl  iiiilnrlv  nlniiu  I  lie  Imi^ 
:i\is  111'  I  lie  llrrM'-ln'iiij. 

A  lilllr  ;iliii\i'  llii-  ii|i|H'r  rllil  nl'  llir  ijilir  iMm'  ;iiiiI  liiUiinU  I  lir 
IIIIMll    >iili'    i-i    \\w(illlll    II  III  rill  Is.    II    riillliil    wllili'    ilnl    I'lirluvil    liy    II 

iiiirriiw  riiii;  nf  liriylil  jirccii.  On  llii'  Iciiiimrtil  ■.iilc  nl'  llir  ili^c.  mihI 
iiImim'  IIii'  i'MiI  111'  il,  is  iiImi  II  liiii^r.  imrriiw.  »i'ri-.ilivi'  iircM.  Tlii^ 
purl  i»  ('ii(lii»<'(l  In   11  sliiliiiiicriiitf  rrllrs  nf  ;;rri'ii  liylil. 

'I'Ik'  nplir  iHm  is  Iiiiik'  mill  rill  licr  iiiirriiu.  Imlli  iinU  liciii;;  riiiiiiiliil 
III)'.  Il  is  i|ilili'  wliili'  .'iinl  ilri'pj.v  |ii;;iiiriilril  jil  iN  niili'r  iiiiil  ii|>|m  r 
liiirilcrs. 

'I'lir  jMclrii  is  111'  J  liylilcr  Ihuxmi  iIiiiii  iisiiiiI.  is  |iliiirily  scrriiliil 
nil  I'illirr  siilc  iiiiil  ii|i|M'iirs  ;is  !i  iiiirriiw  luiinl  III  l  t'Xii'iiils  the  wliiilc 
Im^'lli  of  lilt'  ilisc  Jiisl  licfnrr  its  jiiiu'lioli  with  the  nptir  rirrxr- 
hi'iiil  il  is  slippli'il  with  liri«lit.  nniiiiic-ri'il  ^.'niins.  'I'lii'  criitrtil  purl 
nf  till'  pi'clrli  cliH's  iinl  prnjccl  fur  fnrwiiril  illln  llir  xilrcniis;  i|  np- 
|M'iirs  In  lie  i|iiitt'  niirnnv  while  the  wlinlc  IciikIIi  nf  ils  iip|HT  rilftc  nr 
crol  sci'iiis  nil  her  Wiiv\. 

Accipitriformes 
Kammkiii.kik.h.         .udku  \  1  i.ri  iih;.  liiiiiiiihishiirhiilii.i.  I'liilc  X.WII. 

'I'lit' ryrurc  .  i  is  sliili'-finiy  iiiiil  prt'si'iils  i'\  cry  when'  :i  unmiiliir 
iippciiniiK  r.  ''iH'  Inwi'r  liiilf  nf  llir  fiiiulils  is  cnM'ii'il  with  iliill 
nniii:,'i'-i'i'il  chnrniil.il  \rssils  lliiil  run  in  ii  Mrliciil  ilircclinn.  p;ir:illi'l 
In  till'  sides  nf  I  he  nplic  ilisc. 

Aliiive  the  impilhi  iilliniil  Iwii  ilise  lireiiill  lis  frnlii  il  nn  llie  iijsiil 
siilei  is  ;i  siiimII.  rniinil.  (Iiirk-limwii  p-^ineiileil  pil,  siirrniiiiiliil  liy 
Iwci  ilislinelly  ni.irki'd.  Iirilliiinl  reljex  rinys.  eiieh  liii\iii;;  n  y;i'<enis|i 
Iinl.  On  the  niisiil  side  nf  Ihe  nerve-heiid.  Iiiit  nejirer  llie  l.iller  miiiI 
niiieh  less  ilislinelly  niiliiiied  lli.in  Ihe  depressinn  jiisl  deserilied.  is 
Ihe  seeniiil  niiielihir  re;;inn  with  ils  fn\eii.  Il  liiis  :i  snfl.  indisliiul 
lull  diirk  eeiilre.  The  npl ie  eiilriinee  is  pure  while  with  ;iii  nriinjfe- 
red  eeiilr.il  ,'ire:i  friini  which  .irises  Ihcpcclcii.  This  lindy  is  very 
niiri'nw  iind  liipcis  mi  il  >  upper  nspccl  for  iilmiil  nnc-tiflh  nf  ils  leii;,'lli. 
1 1  I  hen  liecniiics  tniieli  lirniider  ;ind  iihnnsl  envers  Ihe  iiiiler  /nne  nl' 
Ihe  disc. 


I. ill 


CARIN    TJG 


Serpentariiformes  I'i.\tk  XWl  (iitimijirtiiiiit  nl  Siriifiituriits  •nriDiidriim 


Accipitrifonnes 


IVaik  XWl  I 


(ii/IHwlK.i  hartxiliiK 


^B»^^^^^^W^^i^"WfW 


"i 


■ 


CARINATiC 
Accipitriformei 

Um.ii   Km.i.k.      Iliiliiiiln.1  Ii  iiriHuitliiihi^.      I'hili'  WXIII. 

'rii<'filliilll«i->  liiii>ll,\  ii  ilnik  ni|i|i«li-lir"»li.  lllf  liiwrr  lijilf ilijiii.'- 
iliU  III  II  (lull  iiriiMUf-ri'il.  Till'  liiHir  txruniilliil  ix  riivirnl  ^jlli 
rliiiriiiiliil  M'oiiU.  iiiil  io  iliilli'il  with  liniwii  iiiutiirnt  ^'riiiii».  uivitiu 
it  :t  riiiiL'li.  uiMiiiihii'  ;i|i|M','iniMi')'.  A  k'i'iiv  '•lii'i'ii  |M'rvMilr>  I  III'  ii|i|H  r 
jiiirl  iif  I  III'  fiiMilii-  I  In  I  III'  lrlii|Hiriil  ^iilr  nliil  vniii'  ill-l:iiirr  fniiM 
I'll'  ii|i|H'r  I'liil  iif  Ihr  iijilir  ni'i'M'  i'<  n  lirilliiiiil .  uiiilr.  ri>iiiii|  ilnl  -iir- 
riiiiiiilt'il  li\  ii  oiiiiill.  Ii^lil '^rt'i'ii  ri'lii'X  riii^',  wliirli  !■<  JNt'lJ' inrliiNrii  in 
M  lirillitiiil.  iLirriiu.  Kr)'!'!!  iiiMi'iilitr  n'^ioii.  (hi  llir  iiiimiI  oiiji-  nf  I  lie 
iliv.  ,'itii|  nil  ,1  li'M'l  willi  lliii  iii.'iriilii  i>  iiimlin'r  iimi.  of  ii  uriiv  injiir. 
iiirriiiliiilrij  liv  II  f:iri->li;i|M'il.  Iiiiiiiliiiiio  rrflrv. 

Ilii'  iiplir  iii'i'M'  I'lil  rniii'i'  !■>  i|i>l  iiii  1 1.\  wliilr.  iiiiil  iilmiu  il«  iriilri' 
j<  si  IT  w  II  ^1  hirui'  II I  Ml  1 1  irr  I  if  iiiiiiiilr  iiiuiiH'iil  iJiiN.  Tin'  ■■liter  Miiir|.'iii 
■  if  till'  ilisk  i->  linril^'ii'il  »ilh  lihuk  |iii,'Miriil .  ii"  if  ii  »li.iili>\v  wrrr  ciisl 
ll|)ii|i  il  l>v  llic  |M'('lrll. 

\\  III  1 1 -liu.i.iKli  Skv    K.M.i.h..      Ililidilii.i  liiiiiiiiiisfir.     I'l.ili'  \X\I\  . 
Till'  ciiliiriiliiiii  nf  I  111'  ryi'trriiiiiiil  is  iiiii»ll\  ijiill-lirnwii.  llir  linvrr 

i|ll;iill'.'lllls  of  I  III'  lirlil  Kcill^  I'liM'rril  willl  illlll.  iirilllp'-ri'il.  rlli^l'nililll 
IiIikhI-m-scU.  Tlir  liisc  :-  a  Inn;;  wliilr  iiviil.  hIidm'  I'rlilrc  i»  linlnl 
willl  ■iiMimi'  Illlll  iiiviTi'il  willl  lin>  piuiiii'iit  iliils.  'i'lir  (liipilliiry 
iiiiir^'iii"  iii'i'  wliiti'  linrili'i'i'il  willl  lihirk  |ii;,'iii<'iil . 

'riir  iipiHT  liiilf  of  till-  fiiniliiN  is  ciivirrii  liv  ji  iiiiiss  nf  iliill  ^riix 
<|nN.      Till  ri'  is  ,1  Hill  ili'tiiuil  rrlli'X  liriir  linlli  iniiciilir. 

Tin-  |»rli'li  is  MTV  111!;.'!'  :illil  inlilis  wi'll  fnrwiiril  InHjirils  llii- 
IMisliiim  siirfiliT  nf  llir  li'lls.  Kiilli  rxlri'liiilir-  nf  llir  nr^iili  iirr 
rir:illv  \  isiliir  llimnyli  llii-  nplil  liiilliins('n|M'.  TliiTf  illi'  vrry  npaijlir 
iiiTvi-  tiliiis  In  III'  si'i'ii  ill  iiiiv  pni'l  ■■f  llir  rM'u'r'iiinii. 


3??^ 


:iVM 


CARINATA 


Aocipitrifonnes 


I'l.MK  XXXIII       lldliiii'liin  liiiciM-iphiilim 


Accjpitrifonnes 


I'l.ATK  XXXIV  llclidftiis  IcuciHiii.iIrr 


'wr 


-sMr'^; 


tf^TR,  t 


CARINAT^ 
Accipitrifonnes 

KlHOPKAN  KkstUKI..  Tiilliliiinilii.i(il(iil<l(ll!lis.  riiilr  WW. 
Tli<-  |)riiici|i!il  colonilioii  of  the  fiiiidiis  is  ii  liuhl  In-own.  or  l.rowi;- 
isli->;niy.  Tlit-  lower  (|iiii(lriiiil.s  iirc  slrciikfd  willi  oriiri;;c-ri'.l, 
(lioroi.liil  (•M|)illiiri<-.  Ili.il  run  in  »  niorr  or  less  vcrlicnl  diri'diori. 
iUKJ  iM'conic  more  <lisliii(l  .iiid  lirijilitfr  red  jis  tlicv  iiiJiiro.-icli  ||i<- 
ix-riplicrv  of  llic  ficM.  Tlii'  optic  disc  is  m  loriK.  while  oviil.  sliowinj; 
its  inarnins  well  licvond  the  piKnientcd  jind  frln^'ed  peclen.  'I'lie 
centr.d  nrea  of  llie  piipilla  ji|)pe!irs  to  he  hollowed  ont  like  a  e.inoe 
and  the  ix-cteti  does  not  overlap  it  at  anv  point  of  its  circnniference. 
as  is  so  fre(|uenll.v  the  case  in  avian  fundi. 

The  disc  extends  as  far  downwards  towards  the  fnndal  periphery 
as  the  oliserver"s  eye  can  reach.  M  its  lower  extremity  several  small 
choroidal  ca|>illari<'s  can  he  seen. 

The  pecten  has  a  rounch-d.  pyramidal  form,  slopinj;  towards  the 
centre  of  the  disc  at   lioth  .-nds.     It   is  of  a  dull  l.rown  color,  and 

cornijfateil  like  a  photo^rraphic  camera.     .Vl   the  j tion  of  pecten 

and  papilla  are  scallered  numerous  lirown  dots,  so  disposed  as 
to  f;ive  (he  former  thi'  appearanc<'  of  a  weh.  The  upp'  r  part  of  the 
eyejjroMnd  is  (piite  devoid  of  choroidal  ves-i-ls,  hut  is  covered  with 
niimit<- white  dots.  The  fundus  is  nuich  clearer  of  the  retinal  shimmer 
orretiexnoticed  inmost  hirds.  The  two  macular  rej.'ions  are  .list  iuel  I  v 
visil.le.  The  nasal  macula  is  situated  jusi  ahove  the  upper  end  of  lii, 
disc  an<l  aliout  half  a  'liscdeuKtli  on  the  iiuier  or  l>eak  siileof  the  eyc- 
^'round.  It  is  a  dark-lirown  spot  with  a  pale  area  all  aroinid  it.  Out- 
side of  Ihisrcffion  and  enclosinnit  arc  I  wo  dislinct.  pale  >;re<'n  filiform 
reth-x  rinjrs.  the  interior  rinf;s  hein^'  ipiite  free  from  the  white  dots. 
On  the  outer  as|H-ct  of  the  cycKround.  ahoul  one-third  the  leii>.'!li  of 
(he  dis«- above  and  two-thirds  to  (he  outer  si.h- of  the  disc,  is  the  leni- 
j>oral  macular  renioti.  .\t  its  centre  is  a  lijiht.  unty  spot  surrounde.l 
l>y  a  dark  hrown.irea.  '.(h  (lies- area-are  in  their  turn  cruircled  l.y 
a  snudl.  pale-nreen.  reHex  rinj;  alx.ut  (me-fourlh  the  diametc-r  of  IIk- 
(orrespondint;  circle  aliout  IIm-  su|H-rior  macula.  Slender,  opa.pie 
nerve  fil>res  run  out  at  riyht  angles  to  the  disc  on  l)otli  sides. 

I-ITTI.K   HrsTAun.     Tiiroj-  tvlriix.     I'hitc  XXXVI. 

TIk-  fundal  (-oloration  is  mosdy  a  warm  ^ray.  co\ered  with  small, 
dull  orauKc-red  ilols.  In  the  lower  half  of  the  fiehl  anil  on  each  siih- 
of  the  optic  nerve  entrance  is  a  rnunlier  of  choroidal  vessels  of  a  dull 
oraiijic-red  color,  running'  parallel  with  the  disc. 

So  far  as  seen  (he  papilla  is  a  dead  white;  optic  fihres  form  a 
frinue-like  setting  ahout  it.  The  central  zone  of  the  disc  is  covered 
liy  a  mass  of  miiiute.  lirowii,  pi^'ineiit  d<-posits  of  irregular  shape. 
Opa<|ue  nerve  fihres  extend  at  riwht  angles  to  th<-  disc  on  either  sidi-. 
.V  little  (o  the  temporal  side,  aliout  oiu-  disc-length  from  (he  upper 

<'"'l  "f  ll plii-  nerve,  is  a  small,  hrown  spot  like  a  tiny  hole.     This 

macular  area  is  surroiuided  liy  a  lirilliant.  >;reen  reflex  riu^r.  Th<- 
peeten.  of  a  ilark  (-luKolale-lirown  color  and  shaped  like  a  corkscrew, 
comes  well  forward  towards  the  inferior  horder  of  the  lens. 

I  I.U  I 


CARINATiE 


Accipitrifoimes 


I'l-ATK  XXXV        'I'iiiiiiiiiriiliis  (il(iii<l<in'ii.i 


Accipitriformes  Flvtk  XXXVI 


Tilrar  tvlrnx 


CARINATJE 
Strigiformes 

'^A\V\^    ()\M..      Si/niiiuii  iiliini.      I'hilc  WWII. 

On  till-  iiiilcr  ii>|H'('l  of  till'  piipilhi  iiiiil  tilxml  i>ri<-  (lis('-l('ii};lli  from 
it  on  :i  level  willi  (he  upper  margin  of  I  lie  |M'e<eii.  is  a  slight  (iepressiiin 
almost  ijevoid  of  <'lior<ii(lal  vessels.  Its  centre  is  a  dark  red  color, 
and  on  the  margins  cf  the  depression  and  surrounding  it  is  a  liri);lit 
circular  r<'tlcx.  For  some  distance  oiilside  lliis  fo\eal  riiif;  the  eye- 
ground  is  seen  as  if  one  were  viewini;  i!  Iliroujili  a  translucent,  >;ravisii 
mist  or  liazc:  and  I  lie  fundus  lliiis  seen  jfcnerally  ap|M'ars  (o  lie 
jjraiinlar  with  a  few,  small  choroidal  vessels  showing;  here  and  there. 
Inside  the  riiif,',  however,  the  details  are  sirikinulv  clear,  and  the 
coloration  l)ri),'lil  red.  .VImivc  the  macula,  on  the  outer  side  of  the 
disc,  is  a  <|iianti'y  of  dark  pijiiiienl  tieposiled  lietwceii  the  choroidal 
vessels,  hy  con  last  liiakiiif;  the  latter  stand  out  as  of  a  liri;;lit  oran>;4' 
color.  The  inner  as|M'ct  of  the  fundus  a|)pears  yellow:  it  cxhiliits 
numerous  clioroi<lal  capillarii's  whose  yellow  tint  is  distincliy  lirinhtcr 
near  the  inferior  sejiment  of  the  disc. 

CoM.MON    Hakn   (hvi..     Sfrij-  tiaiiimia.      Plate  XXW'III. 

The  general  tone  of  the  eyenroiind  is  dull  j;ray,  with  l)rij;lit  oraiim'- 
red  choroidal  vessels  distrihiiled  all  over  the  fundu'-  except  at  lh<' 
macular  re;;ion.  \i  this  area  the  tint  is  much  ^{r.'iyer,  liein^.  in 
addition,  stippled  with  small,  irregular  lilotclu's  of  orange-red  and 
fira.v  dots.  The  macula,  also  suffused  with  a  deep  ^ray  reflex,  is 
situated  aliove  llii'  iip|M'r  end  of  the  optic  disc  and  nearly  in  a  line 
with  the  Ion;;  axis  of  lli.il  or^'an. 

The  papilla  is  loii^'  and  narrow  with  pointed  ends,  and  appar- 
ently made  up  of  <'o,:rse  while  fi'u-e-hiindles  the  central  portion  of 
which  is  covered  with  minute,  liro,  .  pi^:menl  grains,  that  have  a 
distinctly  n-ticulaled  ap|M-arance.  Ttiese  white  fibres  lionler  the 
nerve  head  all  around. 

The  dark-lirowu,  convoluted  pecleii  is  lar^c  and  extends  well 
forward  towards  the  lens.  Krom  liolh  sides  of  the  <•  radiate  a 
few,  dull-t:ray  fil)rcs  that  stretch  a  short  distance  across  the  fundus 
and  I  hell  disa|i|>ear. 


I. -Hi  I 


SVP^^VUTi^'^ 


CARINATiE 


Strigiformes 


Pi.atkXXXMI 


Si/nilniii  (iliiro 


Strigiformes 


Platk  XXXVI It 


.SVr/x  H'Dintica 


.ttiWRt      \^_  M 


CARINATiE 
Psittaciformes 

<>ll\N(.K-\\  l\(,KI)    I'miIKH.       Clirilsolis  (imtKlllKI.       I'lilll-    \\\IX. 

Tlir  iictHTiil  ciilor  of  llir  fvr>;r<mti(l  is  ii  ilfc|)  cray,  liiilcil  witli 
Imtr.  'I'hr  loHir  scclcir  iiiiil  llir  iMi-ipliiiMl  Zdiic  arc  siiiriisnl  willi 
pi'ik.  I  hi'  liink«r<>iiii(l  KciuTiilly  Ix-iiin  pniKlu.iIrd  willi  iiiiiiiit<', 
iliill-yrlldw  ilols.  Tlif  iiiiiciiliir  iircii  is  siliialcd  lownrds  llic  iiiisal 
si<lc  (if  Ihr  <lis<'.  a  lilllc  aliiixf  the  ciiil  of  the  |M'(lrii.  Il  is  shijlilly 
(Ifprrsscd  and  enclosed  witli  a  liriKld  Iml  pale  jrreeti  re(lex-rin>;. 
Kxlendini;  from  llie  eireuMiferenee  of  lliis  eirele.  slijtlilly  aliovi-  as 
well  a>  lielow.  are  a  few  Irafislneent  filires.  pale  );ri'en  in  tone:  and  al 
its  eenire  is  a  dark-;;ray  dot  or  depression,  with  a  small,  faini  lialo 
exlendinn  from  its  upper  edjje. 

Tl plie  nerve-liead  looks  as  if  i|  were  <dm|)osed  of  <-oarse.  white. 

opa«|ne  tihres.  which  form  a  fringe  all  around  the  <li'eply -colored 
peeten.  The  papilla  is  lonj;  and  lioat-shaped  and  its  outlines  can 
lie  traced  the  whole  leny;tli  of  the  peeten.  Many  fine,  ^ray,  opai|iie 
nerve  filires  extend  from  the  margin  of  the  papilla,  cross  the  liaek- 
;rrouud  of  the  eye  and  are  eventually  lost  in  the  fundal  tissues. 

The  ileep  lirowii  [lecten.  seen  from  aliove.  has  a  spiral  form,  with 
a  ta;,'  or  tail-piece  al  the  up|H'r  end.  A  lateral  view  shows  it  to  !«■ 
plicated,  like  a  fan.  It  stands  well  forward  towards  the  lens.  esp<'- 
<ially  its  lower  half.      Il  has  a  dark  lirown  color. 


Kakai'o.  Owl-l*arrot.  Stringops  li<ihr<ipliliis.  I'lale  XI,. 
The  eyc^rri.und  is  oran«e-red  stippled  all  over  with  lijjliter  orange 
dots.  The  lower  half  of  the  fundus  has  a  larjje  numlier  of  minute 
dark,  reddish-nray  depots  of  pijiment  intermingled  with  lifiliter  dots; 
also,  a  jfreat  many  choroidal  vessels  run  in  a  \crtical  direction  over 
the  field  of  view  on  either  side  of  the  optic  entrance.  Tlie,\-  lieeoni'- 
more  minieroiis  towards  its  lowt-r  [M'riplier.v. 

The  nuicula  is  placeij,  as  in  Owls  f;<'"<Tall.\-.  on  the  temporal  side 
of  the  optic  papilla,  aliout  one  dis<'-l(>iii;tli  from  its  upper  end  and 
half  that  distance  to  th<-  temporal  or  outer  asjM'et  of  the  fundus.  Il 
is  a  lirif;ht  orange-red  area  surrounded  Ky  dark,  red-gray  pigment, 
like  a  shadow.  There  is  no  circular  sheen  around  il,  such  as  has 
U'c'i  noted  alioul  other  avian  fovea'. 

The  optic  nervehead  is  whil<',  jind  along  its  centre  ap|M'ars  ,-i  nel- 
wi.rk  of  iiiinutc,  l.rown  pigment  dots  <luslering  around  the  >ides  of 

I  he  peeten.  .V  feu  rtliite  opa<(Ue  nerve  filires  extend  a  sliorl  distance 
on  either  side  and  altout  the  upper  <'nd  of  the  disc. 

The  lilaek-lirown   |H'cten  extends  the  whole  length    of  I  he  disc. 

II  is  ralher  straight  in  its  upper  half  Imt  is  more  convoluted  towards 
the  iow<T  (lart.  where  it  is  (juiti-  massive  and  resenddcs  a  corkscri  w. 
It  comes  Well  more  forwan!  towards  the  lens,  so  that  il  more  nearly 
resenililes  the  same  organ  in  the  Burrowing  Owl  than  in  the  I'arrot. 


!3Hj 


«    h    » 


^^ 


■W^" 


■PJPS" 


CARINATf 


Psittaciformes 


Platk  XXXIX  Cliri/xotix  (imii'diKi 


Psittaciformes 


I'l.ATK  XL  Strhiijopn  hahroptiliix 


^ 


CARINAT^E 
Psittaciformes 

(HiKAT  Si  l.l'IH  H-<  HKSTKII  ('(KKATIM).  Cllnllllll  (/lllirild. 
I'liltr  XLI 
Till'  liiukKromnl  is  of  ii  fairly  iiniforni.  linlil.  uniyisli-ldnr  color, 
spriiiklnl  with  iniiiiili-  while  <iols  iiilcrsiMTscd  willi  iiiiiiiv  less  iiimitT- 
oils  Imt  >oiiif\vliiit  liir^tcr  (lark  uriiy  deposits.  The  iiiiieiilii.  ill  Ihe 
upper-inner  (|ii.'iilrant.  is  an  irreKnliirly  round,  lijilit  hrownish  area 
whose  dianielcr  is  half  Ihe  ilise  length:  nnil  whose  periphery  fades 
into  Ihe  surrollndin^r  Kray  of  the  fundus.  The  upiM'r  sixth  of  Ihe 
loiiK.  pointed  [lapilla  is  distinelly  \isil>l<>  where  il  is  not  covered  l>y 
Ihe  iiKJented  peeten.  whose  twelve  douMe  folds  have  a  <'orkscrew 
tertnination  aliove.  I'orlioiis  of  the  disc  liorders  <an  lie  seen  from 
aliove  Ihrou^'h  the  plications.  e\ripl  at  its  posterior  terniiiial.  where 
the  dark-hrowii  mass  entirely  covers  il.  Kainl.  whitish  lines  of 
opa<|Ue  nerve  tilires  extend  from  the  margins  of  Ihe  uppi-r  half  of 
the  disc  a  short  ilislance  across  the  cenire  of  the  eyef;round. 


Coraciiformea 

L\((illlN<i    KlNiiHsllKli.      Diirild  illija.''.      I'lale  \I,II. 

The  fundus  oculi  is  in  >;eneral  of  a  liKJil  fawu-nray  color  minKle<l 
with  irrenularly  sha|>ed  white  or  >;ray-while  dots.  exce|)t  in  the 
neifjhliorhood  of  Ihe  optic  nerve  where  it  is  oran«e-red.  like  Ihe  jil""" 
cast  on  Ihe  sky  liy  Ihe  selling  sun.  The  opiic  nerve  cnlranee  is  loii^ 
and  narrow:  il  is  while  except  alonj;  its  central  area,  which  is  oraiifje- 
red  striped  with  lirown  pinmenl  dots.  .\  larjje  numlier  of  opa(|Ue 
nerve  filires  run  out  on  each  side  of  tin-  optic  nerve  and  at  rif,'lil  angles 
lo  it.  The  iM'clen  is  very  lon«  and  narrow  and  has  Ihe  api«arance  of 
a  lirown  ccnli|M'de. 

The  macula  is  very  conspicuous.  .Mioiit  half  a  discdennlh  from 
the  up|H-r  end  of  the  n<rve.  towards  the  nasal  side,  is  a  small,  round, 
dark  depression,  surrounded  hy  a  very  narrow,  hrifllil  jireen  riufj. 
This  circh'  cnclosi's  a  sniaHer  area  that  is  of  a  darker  Kray  and  devoid 
of  till'  dots  seen  al  other  parts  of  the  eycjrronnd.  The  fovea  nasalis 
always  apiM'ars  directly  opposite  the  pupil;  lliere  is  no  fovea  tempo- 
ralis visilile  to  Ihe  ophllialmosco|H'. 


m] 


II^^^PP 


TnwrTTsr^Tvm 


nRSRPVf^nMM 


^m 


fmmm 


mv 


CARINATiE 


Psittarifonnes 


Platk  XLI 


('(uuliui  {lalrrlld 


Coraciifonnes 


Pl-^te  XLII 


Dacelo  giga.i 


wmmmmvmmmmm 


mmmmmmam^Fmnntm^mii'^mm 


CARINATA 
Coraciiformes 

Hl.\(  K    lliiUSIIII.I..      SpiiijiilohiiK  ililtillil.1.      I'liltf  \l.lll. 

Tlic  principal  color  of  the  ryrnroiiii<l  is  <liill  Kniv.  iiili'rs|NTM'<l  for 
soiiir  <li>liiiiir  iilioiil  llir  optic  nerve  ciilriiiicc  willi  ii  liiass  of  tine 
opaijiic  fil>rcs  llial  fXtcml  alioiit  a  ilisc-icM(,'lli  over  I  lie  fiindiis.  He- 
voimI  (lie  filtres  are  several  dull-colored  choroidal  capillaries  llial  cross 
llie  fiiiidal  field  in  a  vertical  direction.  Near  the  macular  region  llie 
fnn<lus  is  illnniinated  iiv  a  lirilliant  yray  iridescence. 

The  optic  disc  is  a  lon>;.  while  oval,  that  exii'nds  downward  and 
a  liltli'  inward  towards  the  inner  or  lieak  side  of  the  head.  The 
IM'cten  is  very  larnc.  the  lower  .se>{nienl  iH-inj;  carried  far  forward 
liehind  the  iris;  it  presents  .s<'rrated  nnirKins. 

The  inacniar  renion  is  ((uite  <'ircMlar  and  is  red-l)rown  in  color. 
\\\  iinier  circli-  is  dead  white,  wliile  the  foveola  is  represenled  l>y  a 
dark-red  central  spot.  There  are  two  liri^lit  rinjjs  around  the 
macula  of  an  iridescent,  hlue-^'ri'cn  color,  the  fundus  helween  the 
two  circlets  iH'iiiK  a  \'\ii\i\  luminous  ^ray. 

KiiiDl'KW    \i(;irr.lAH.     ('(ipriiinilijiis  viiropiim.      Plate  XLI\  . 

The  eyet'round  apiM-ars  oran^'e-red.  everywhere  stippled  with 
small,  red  and  lirown  patches  of  irregular  shai«'.  ScalliTcd  aliout 
are  several  pigmented  an-as,  such  as  one  s<'i-s  in  the  eyes  of  human 
sul)jecls  with  disseminated  clioroiditis.  There  are  a  few  choroidal 
vessels  in  the  low<'r  half  of  the  fundus.  These  an-  fainll\'  out  lined. 
Iiut  they  >;ive  to  that  part  of  the  eye^'rouml  a  deciH-r  red  than  the 
remainder  of  the  hackjjround. 

The  optic  papilla  is  short  and  liroad.  The  atitero-poslerior  view 
with  the  mirror  shows  it  as  a  dull.  >;rayish-»\liite  iiody  larf;el.\'  coveri  d 
with  lirown  pi);mcnt  dots.  Its  mar^'ins  where  it  is  not  iilis<iiied 
■  y  the  mass  of  the  |M'cten.  is  miK-h  linhler  in  (iilor.  Uadialiiin  I'om 
the  sides  of  the  disc,  and  exIendiuH  for  .t  short  distance  i.-ii  .'illier 
.ide.  are  a  few  wliile,  opa(|Ue  nerve  filin  s.  whirli  arc  lif;l't  ifr.iy  ^did 
hecome  less  distinct  on  the  outer  side  of  II. e  papillii. 


1IH<1 


CARINATiB 


Coraciifonnes 


Pl-vte  XLIII  Spn(ji)U>bii.i  mlraliis 


Coraciiformes 


Pl.\te  XLIV  Capriiiiiilyii.i  vurnpfus 


CARINATJB 
Cuculiformet 

KiKiii'KW   ('iiKoo.      (' lulling  viinorim.     I'liilr  XI.\'. 

'I'lir  I'vcKroiinil  i<  (jriiy  willi  it  •'iiir((<">lii>n  "f  fawn,  cvcrvwlirrf 
liopriiikli'il  ttilli  Kriiyi-.li-wliili'  ilots.  'rowiiriN  llic  Iowit  i|iiailriiiil<> 
i(f  llii'  fiiiHlu*.  in  piirliculiir  111  tlii'  cvlrriiiilv  of  llic  |MM-trM,  llir  limk- 
>;r(niiiil  i*  »ii(Tiis<-<l  with  ii  dull  pink.  N'mr  the  ii|ilic  ihtvc  i>n  rillicr 
>.i<|c  lire  x'viTiil.  pliiinly  visililo.  (>riin),'f-rril  cliiirniiliil  vrsscU. 

Till'  iiiaciila  i»  M't-ii  almvc  tlir  iliw-  tnwariN  IJic  na-al  <iil<'.  'I'lii* 
ari'ii.  slightly  ri'd  in  liini-.  ii|>|»ciirs  il)-|ir<-^<M'il  Im-Iihv  Ihf  fuiidal  siiifaci-. 
altlioiiuli  no  (Icfinili-  f(>\ra  is  \i«ililf  with  tin-  mirror. 

Till'  papilla  is  aliniiNt  niniplclcly  covcrcil  liy  llir  p<'<-lcri  no  Ijial 

•  inl.v   lln>  iiiitlinrs  of  llii'  fur r  can  Im'  si'i-n  l>y  llir  aiiliriiir  |«i>lirii>r 

iii>i«>iti<iii  of  llif  i>plitlialim>sci>|H'.  Where  llie  papillary  niarjiin  i> 
xi-ilile  it  shows  exireiiii-ly  while. 

The  iK'clen  also  exienils  well  iihove  anil  lieliiw  the  ilise  lerniinals 
anil  projeets  deeply  into  llie  viln-ous  eliiiinlHT.  It  ap|M'ars  liy  the 
mirror  lo  lie  a  ehiH'oliile-ltniwn  color.  (lpai|He  iier\e-til>re  railialions 
are  seen  In  oriKinale  al  the  disc  liiiirKins.  whence  I  hey  cross  I  lie  liack- 
Uronnil  and  finally  disapix-ar  fnim  view  al  or  near  Ihe  fiiniliil 
IK-riphery. 

Piciformes 

Si  i.i'iii  n-iiHK.vsTKK  Till  IAN.    Hliiiiii  plid.iliiM  liriiKitiin.     IMale  XL\  I. 

The  eyenronnd  is  ilnll  uriiy  in  color,  rallier  rej!iilarly  s|Mitleil 
wilh  whilish-tjray  dols.  The  optic  papilla  is  apparently  composed 
of  short,  coarse,  white  tilires  which  form  a  sort  of  frinue  all  round  its 
mar^'iiis.  .Monn  each  of  its  sides  and  parallel  lo  its  lon^'  dialiieter  a 
few  orannc-rcd.  choroidal  \  essels  are  seen.  {{adiatiiiK  from  the 
papillary  circiimfereni-*'  an-  numerous  opai|iie  nerve  filircs  that 
extend  to  Ihe  fiiiidal  |MTipliery  across  Ihe  eyejrronnd  on  all  sides. 
The  iM'cteii  is  almost  lilack-hrown  in  color. 

.Mdive  the  end  of  Ihe  optic  nerve  entrance  and  alioiit  half  its 
length  111  the  nasal  side  are  three  dark-lirown  spots,  elnslered  lop-llier 
and  "Urroiinded  hy  a  small  uray  reflex. 


I  1«4  1 


^S^^^P^ 


CAIUIfATiB 


Cuculifonnes 


I'l.ATK  XI.V 


('iinilii.1  raiiDriin 


Picifonnes 


Pl.\te  XLN'I  RhiimphttMfii.i  Iwmatii.t 


m 


■E7*«^    "id^M.  >  ^  af  'j-iii 


CARINATiC 
Piciformes 

(■Mv    WciiilJfF.i  K^  II.      (iiiliinixiiiiipfiiiiilliM.       I'llili'  \l,\  II. 

'I'lir  I'liMiliiN  iH'iili  i'.  iliill  ;;rii,\  liiiliil  with  \flli.»  iiiiil  iii'iirl.\  iiiii- 
foriiilv  <'liiin.'i'<l  u  illi  iiiiiMitc.  uriiv  ilnli.  A I  tlir  siiiH'riiir  Icriiiiiiiilioii 
nf  llii'  ri|ilii'  ili«i'  {nil  III!'  iiii>mI  '•iili'i  it  .1  '.iiiiill  ^I'liv  ili'|iri'-.<iiiii,  |>iirll> 
oil  I'll  Ml  Mill  Ilk!  II  ri'iilral,  wrll  iiiiirki'il  iiiiil  uli<li  iiiiik'  »liili'  'li'l.  Willi  in 
I  Ills  iiri'.'i  iiri'  aUii  m-mtiiI  i;iililrii  viiinw  ilnU. 

Till'  iiiltlilifs  iif  llii'  ii|>tir  iirrvf  riilr:iiii'i  iirr  »rll  ilrtiiii'il,  Miiil 
Mil'  ii-iili';il  iin-ti  III  ilii-  |iii|iillii  ill  iU  iiiiiuii  vniIIi  llir  iii'iliii  i<.  iliill 
iir.iiiL'i'  "lipplril  nilli  iliirk  lirnvvn  |iii;iiiriil.  'I'lir  |iii|)illii  it  rriiip-ii 
H  illi  iiijirM'  H  liilr  til  in  ».  .\  liiru"'  iiilliil-.rr  nf  lr:ili><liirriil  iiri\r  lilirr> 
niiliiili'  rrnlli  till'  ril^r  iif  I  III'  ii|ilir  iHm'  nil  nil  >iili">;  llirv  IhthIiii' 
fc'iiiilrr    iiiiil    rniiilrr    .in    IIicv    ii|i|ii'niirli    llir    fiiiiiliil    |H'ri|iliri'\    nml 

lillilll.V    lliMI|l|M  ill'. 

'I'lif  |H'rli'ii.  Ill'  till'  ii>iiiil  chiM'iiliilr  lirnnii  rnliir.  rrvi'iils  si-mtmI 
rnl'k«rri'W  rniiMillllinli".  Il  rnliir»  tti'll  fiirw:iril  InHiinN  I  III'  lrll». 
mill  lirrx'llU  ii  lililosiM'.  rll|li-'<liii|H'il  ,'i|i|H'iirtltirr. 

(illKATKH  SlItTTKII   \Vl  M  MH'Kl  KKII.        Driinllllll.l  III  Dl  IlllriiriilHl.l   llllljlir. 

I'hil.   XI.VIII. 

Till'  cnlnr  iif  I  III'  ryi'urniinii  is  a  iliill  lull  ijrtiiiilr  .univ.  iiilri°>|M-i-M'il 
uilli  .1  liirKi'  iiiiiiilirr  nf  siiiiill.  ;;riiv  iliil>.  lit'lnw  llir  iiplii'  ili->r  iiiiil 
|>rrli  II  lire  il  fru  fililll.  nl'illl(.'i'-riil  I'linriiiilill  V"'>M'U.  Tile  oplir  iliv 
is  .'i|i|iiiri'iillv  niiiilc  up  uf  ii  iii;i-.-  nf  lirilliiiiil.  uliilr.  nrrvr  filirrs, 
Mry  slinri  .iiiil  lliiik.  In  llir  fnriii  nf  niiliiitiniis  frniii  llir  niiir^'iiis 
nf  llir  piipillii  luwiinU  I  III'  riimhil  iHilpiirrv  iirr  iiiiiiiv  ^I'l.^  npiii|iir 
lirrvr  tilirrs  lliiil  iip[M'iii'  In  niriipN  ,1  philir  liiwrr  lllilli  llli'  ullilr  rlr- 
iiiriils  nf  Ilii'  ilisr.  Till'  |h'i|.'Ii  Ii.is  Ihrri-  I'lirksrrrw  I'liiivnliilinns  nil 
till-  ilisr.  wliili'  iN  Ihwit  p^irl  rnriiis  ;i  rlllli->li,ipi'il  lii:i»  nf  ,'|  ilri'p 
iliiM'nliilr-lirnHII  rnlnr  lliJil  iiplH'iir>  Ini-niiir  wril  fnl'W:iI'il  InWiinls  I  111' 
li'lis. 

Tlwrr  M'riiis  In  Iw  niily  niir  sinsilivc  ii'iilriil  iirrii.  This  >in).'li' 
nnirlilii  i>  nil  (III-  liiiMiil  siiii'  nf  llir  pi'ili'ii  iiliii  Inis  Ijii-  ap|M'Ml'iilii  i-  nf  ii 
lirilliaiil.  wliili'.  rniiiiil  ilnl.  llir  fillliiils  Mirrnllllilili^  il  iH'ili):  a  lilllr 
ilarkrr  lliiin  llir  tfrliiTal  rnlnr  nf  tlir  ryi'iJiiMinil.  Tlir  >iirrniiiiilin^' 
L'ray  ari'ii  iiiakr-  llir  wliili'  fiAi'a  -..'anil  «rll  fnrwaril  alinn-l  as  if  il 
wrrr  arliially  sihialril  in  llir  vilri'inis.  No  rclli'X  riii)i  ran  lir  mtii 
ariiiiiiil   il. 


Hlli  I 


'naemwft 


«SPB^59«a»B" 


^■P-«W 


CARINATJB 


Piciformes 


I'l.Mt:  XI, Nil  ('niliirii.i  iiriii>!i(iiiili. 


Piciformes  i'l.vrr,  XIA'III  Dri/ohalr.i  irl  DfiidriH'oiniK  major 


jiWBSP 


^^m^^mm^^s^m^^f^K^^^i^m 


CARINATiE 

Passeriformes.     .1.  >U>nMM>i»i.    Tjininiililir. 

|)i;i(H\    'l"\i(\\T.      I'ltiiidiiit  (lirhiiinii.i.      I'ljitr  XMX. 

Till-  I'M  lmmpuikI  is  Iduc-nriiv.  cM't-vwlicrc  >|irinkli'il  willi  iiiiiiiilc, 
Kl;i\  <li>ls.  'riicsi-  <Iu|n  tire  xi  closely  piifkcd  on  llif  upiHr  liiilf  of  llic 
fiuidiis   I  lull   llu'v   '.'i\('  il   .1  ilisliii((   siKciy  iipiH-iiniiicc.     Uiiiiiiiiif; 

ill  liuhl  tiufiU-  lo  lillicr  >i<l<-  of  I  lie  opiic  pjipillii  iirf  iirrons  diiM- 

wliilr  opiHUlc  ri'TM-  filirc^:  lliry  cxlciul   well  iicross  (lie  cycjrroiiilil. 
Al   liiilil   iiMulcs  lo  I  he  opiic  ilix-  low.iriU  I  lie  iiiisii!  sine  Mliil  .1  lilllr 

,ilio\c   ils   >iiprrior  fii<l   is  :i   ilciisc.   pMlc-liliif.   ) Iiilf   mass   lliiil 

iippiMis  lo  Mirrouiid  llic  I'ovfji.  A  linlil  l>lii<-  redcx  riiis  nlso 
riicirrlcs  llii>  iiri'ii. 

Thi'  opiic  iicrvc-rriliiiiK'c  is  loiij;.  narrow  am!  wliitc.  lis  ccnlri' 
i>  stippled  Willi  a  few  lirown  pi^nicnl  ilols  and  il  is  liordcrcd  all 
ai'iiiml  willi  -.ymmrlriiallv  placed  Idack  pifimenl  v'raniiles.  'I'liis 
pifimeiited  mar>;in  \aries  a  lilllc  in  individuals.  'I'lie  Ma.'k-lirown 
|M-clen.  Ions;  and  narrow,  exli'iids  wfll  licliind  I  lie  ed>;e  of  llic  pupil 
Ml  llial  a  porlion  of  il  cannol  Im'  sci'U  lliroiiu;li  llie  mirror.  The  upper 
pari  is  vrralcd  !>iil  llic  lower  half  is  more  of  I  he  corkscrew  l,\  |>«'. 

Passeriformes.     />'.  .\rnvi>\ioi)i.     IliriiiKliiiidn . 

Kl  HiifKAN   (lllMNK^    SwM.l.oW.      II  Initidn  rii.ifiid.      riale  L. 

The  s;eneral  color  of  I  he  eyi>«roiind  is  warm  Kray.  linled  >li«hlly 
,  P  \(llow  or  liiilf.  and  covcrcil  willi  miniili-.  didl.  yellowish  dol>. 
Sivr.il  pale  orange  iclioroidali  vessels  arc  sci'ii  near  llic  iip|MT  c\- 
Iremily  of  the  opiic  iicrve-enlraiKc.      There  are  \  isilile  Iwd  maii-lar 

(•(.(rioiis n  each   siile  of  and  alx.vc  llie  npiMT  end  of  the  disc. 

They  show  as  Miiall  lirown  areas  or  dol>  in  llii  c\ej,'ronnd  Siir- 
roundin;,'  lln'  tenipor.d  nia<nla  is  a  s|if;lit  rellcx.  a|ipareiill.\  com- 
posed of  inimile.  liri«lil  yray  dols.  The  macula  on  llu'  ii;;sal  si.h- 
is  (|iiilc  dcMiid  of  I  his  rellex-rim;. 

The  opiic  papilla,  loim  and  narrow.  Ia|«rs  al  its  upper  end.  On 
.ilher  sill.'  of  the  disc,  iiid  al  rij^'lil  aii;.des  to  il  ,ire  a  few,  fin.',  o.iii- 
^;ra>   opaque  ner\ f-HI'ii  s. 

'I'lie  ehocolali-lirouh.  convoluted  pecleii  is  i|iiile  narrow  .il  its 
iiiiietion  with  llic  opiie  nerxi'.  liilt  il  i,'iadiiali.v  liceonics  wiiler  and 
more  mas   ;\('  ..s  it   appro.e  lies  the  leiis. 


1(W  I 


m 


CARINAT^ 


Passeriformes 


I'l.ATK   XLIX  I'Hiiiiiiii.i  (lirhiaiiiin 


Passeriformes 


I'l-ATK,    L 


lliniiidii  riiKlicd 


HfHWffiffi^m^^^M^Hf 


r.w>i     -Vns'^   i'^;' 


CARINATiE 

Passeriformes.     II.     Tiirdiihr. 

Hi. I  iiiiui).     sidlla  xiiilis,     I'liili-  LI. 

Tlic  jjciicnil  liliit'-j.'r,iy  cDlorin;;  of  I  he  rycjfroiinil  is  iiiiidifii'd  \>y 
iiiiinrroiis.  iiiii-piiinl  il(il>.  Tlic  piinctiilc  il<-|«>sit>  iicjir  tin-  |>fri|ili<Tv 
iissiiirir  11  iriiiri'  or  less  diill-Koldt'ii  or  oniii^r  tiiil,  ii  coiidilioli  also 
noliird  just  Ix'low  the  |H'ctcti.  Tilt'  cloiiKiitcd.  ovoid  optic-  dis<'  is 
xvliilc  Kniilc  woolly  iit  its  iiiiirKiiis)  jiiid  coMTfil  jilinosi  entirely  with 
the  voi.ivoliited  |>i-eleii.  wliicli  is  \eiy  liir;,'e  when  eoiiipnred  with  the 
si/e  of  I  he  eye.  Il  is  of  the  usual  diill-l)rowii  color  and  has  "  frilleil '" 
Itorders.  On  the  inner  or  nasal  si<le  and  near  the  lower  part  of  the 
optic  disc  is  an  oraiine-red  area,  containing  chiefly  choroidal  vosels 
with  Mack  pigment  grains  lietweeii  IIk-iii.  This  red  area  extends 
a  little  to  the  letnporal  side  of  tli<'  disc.  sulise(|ueiitly  iiicrjiiiif;  into 
the  dull  orange  color  lielow.  On  <>ither  side  of  the  disc  and  radialin^ 
from  it.  are  niiineroiis  filiform  nerve  rilires  whicii  cross  the  l(ack;,'roiind 
ainiosi  to  its  |M'riplicry.  In  an  area  a  disc-leiifjth  to  the  nasal  side 
of  the  pa|)illa  the  white  dots  of  the  fiindns  are  dcciiledly  fainter  anil 
much  closer  to^lether  than  elsewhere:  in  this  rej;ioii.  also,  there  is  a 
rellex  plaiiil.v  marked. 


■-■y; 


WllKVTKXH.     S(i.rit(>l<i  irnaiitlir.      Plate  l-II, 

The  fiindal  coloration  is  pale  j,'!"'!.^'-  with  a  dense  mass  of  jfrayish 
while  dots  |><-riiieatin<;  the  eiitiri-  liack^'roui>d.  .'^liKhlly  aliove  the 
upper  lermination  of  the  optic  nerve,  and  towards  the  nasal  side  of 
the  |M-cteii.  is  a  well-defined,  round,  whitish  macular  region,  much 
larger  than  the  small  spots  lli.it  covei  the  whole  of  the  surrounding', 
duller  eycitround.  This  white  area  is  i'  •  losed  l)y  a  lirilli.int.  Iilnish- 
f;reen  circle,  whicli  ap|H'ars  more  prominent  and  iriilescenl  in  nature 
than  is  depicted  in  the  draw  in;;.  The  optic  papilla  is  .ilmosi  entirely 
oliscnred  l(y  the  peeteii;  il  is  Ion;;  .ind  narrow,  with  an  irre;;ul.ir 
outline. 

On  the  nasal  side  of  the  nerve-head  are  a  few  short.  oran;;e-rcd. 
choroiilal  vi'Ssi-ls  with  a  few  dots  of  j)i;;menl  lik<'  pepper  ;;i;m?is 
sprinkled  liet  ween  them.  Kslendin;;  fnim  Ixilh  niar;;ins  of  I  he  opi  ie 
disc  across  Ihe  fundus  to  the  i«'ripliery.  are  numerous  line,  opaque 
nerve  filires.  the  upper  omc>  on  Ihe  nasal  side  I  teriiiiiiatiny  at  the 
macular  area. 

The  |)ecten.  red-hrow II  ill  color,  loll;;  anil  narrow,  appiars  to 
lie  Iwi-ted  on  ilvlf  like  a  rope  or  a  eiirkscrew.  Its  inferior  end 
extends  lieyond  that  part  of  Ihe  e.M'Kroiind  shiiwii  in  the  piiluiv.  Iiiit 
it  prolialily  comes  well  fiirwiird  towards  Ihe  posterior  surface  of  the 
lens. 


I  I""  I 


CARINATiE 


Passeriformes 


rL.\TK  1.1 


Sidii''  .ilc'i.i 


Passeriformes 


Platk  LII 


Saxinild  iriiiDilhi' 


CARINAT>E 

Passeriformes.     />      triniiill'iltr. 

llursK   S:'\HH()W.      I'li.isrr  il'umnitiviit.      P1iil<'  Llll. 

Tlir  i,'('ii('riil  cnlor  of  I  lie  fiiiiiiu^  i>  [Mitt-iiray  lovcri'd  willi  very 
filii-  while  dills.  clD-icIv  |)iirl«-il  Ih^cMIht  ill  I  In-  miiciiliir  ;irfii.  Tlii'V 
fiirm  ii  liylilcr  /.one  a  lilllc  atiovc  Ilii-  ii|i(«m  rxlrriiiilv  of  llu-  ihtIcii 
anil  lowaiils  llii'  nasal  siilc  iif  I  he  iIi-m-.  Krimi  the  <ircninf<'rfiiri'  uf 
I  lie  opiir  ilisc  a  hiiiif  ininilicr  of  railicr  lonu.  opai|iif  \\vr\r  filtrcs 
run  in  railial  fashion  lowani-  I  In-  (MTipiirn  of  I  In  liindiis.  'I"h«' 
papilla  appi-ar>.  whrii  visililr.  I"  In-  (■<)ni|M-.^<Ml  of  irrcfinhirly  slia|M-<l. 
Iirilliani  while  Ixinilles:  il  can  liarelv  lie  imllini'il  willi  I  he  mirror 
except  al  the  iip|«T  (ami  narrow  end  of  I  he  iiecleii.  The  p<'<'leh 
has  a  deep  red-lirown  color,  and  its  free  exlreiiiily  is  lull};,  narrow 
and  of  the  corUserew  l.\  pe.  The  lower  se;;nicnl  of  I  lie  orjjaM  extends 
\.ell  forward  towards  I  he  lens  and.  Iiciliir  larile  and  massive,  coiii- 
pletely  cover*  the  pupil  and  makes  il  impossilile  to  olilain  a  lateral 
view . 

\  vliiKi)   Hi  VTlMi.     ('i/iiniixjiizti  nr.siii)li)r.       I'latc  I.I\'. 

The  ii/niniiiiiil  i^  dnll  anty  shaded  to  Imt)'  and  licsprinkled  with 
vcr.v  mimile.  i.'ra.\  ish-while  ilol>,  'I'hesedols  coalesce  at  the  macula, 
where  they  form  a  soft,  round  .irea  liordcrcd  liy  a  linlil  reflex.  The 
siiiftlc  macular  reirioii  and  fovea  are  situated  a  little  ali.ive  the  np|M-r 
end  of  the  pecteii  and  towards  the  nasal  siile  of  tile  optic  nerve. 
The  |>ecteii.  M'ry  lar^re  and  niassi\e  for  the  si/e  of  the  eye.  is  of  the 
usual  choeolale-lirown  colour:  il  i*  more  or  less  clnli-shaped.  ami 
extends  well  forward  lowariK  the  leiis.  Where  the  peeleii  joins  the 
rclin.i  il  is  ver\  irrciinlar  in  -liapc.  The  peileii.  whose  onlline  is 
i|iiilc  irrcyiilar.  <-o\ers  the  papilla  enlirely  *o  that  it  ap|M'ars  to 
spriiii;  ilireell>  from  the  retina  willioiit  ^howiiiy;  the  white  dis<'  mar- 
;,'iii.  I'Voni  the  *ides  of  the  apparent  root  of  the  pectcn  a  few, 
whitish.  opai|in-  ncr\e  lilires  cros*  I  he  field  of  \iew. 


17.il 


CARINATiE 


Passeriformes 


I'l.ATK   LI  1 1 


I'dsxcr  (loiHi'xhni!' 


Passeriformes 


Pl-ATK  LIV  Ci/aiKLiplzii  irrslcitliir 


CARINATiE 
Passeriformes.     />'.     I'linidiicidd . 

I.WV    Kllll)   <il     l'\IIVIH>F..      I'liniliii    liiirii.       I'liilr  I.\'. 

rin- i\ci,'r(iMiiil  is  \<>llii\vis|i-i;ni,\  iiv  klijiki  rolnr.  iiiiil'iiniilv  lovri-fd 
with  :i  (liMsr  iiiiiss  i.r  liiilllllc  while  iliilo.  lluil  iirc  >llliill<T  Mliil  diliMT 
:il  lli<-  iii:iiul;ir  rruicpii.  A  few  iliill-riMl  cliiiii  iiliil  (MlMll.irirs  .iic 
visililf  ciri  till'  liiwrr  |)iiil  iif  till'  fiiiiilu-.  uriir  llir  ii<Ti|)licrv.  Tlir 
oplic  iirr\r  lifiiil.  iliill  wliilr,  liiiif;  mill  iiiirrow.  Iiii>  ,1  riiiiriilnl  ii|>|mt 
riiil.  In  I'lilirc  iTiilnil  :iir;i  ii|)|HMr>  ii>  if  il  wrvr  .-i  iiijiss  iif  line, 
liniwii  piu'iiiriit  liiil-..  'I'lir  |«Tlrii  i-.  cxci'iiliiiiitilly  liiiiu,  riillicr  tiiir- 
liiw.  Npirjilly  :iir.iiii;cil  ;iiii|  cxlcriil-.  liryiiiiil  llir  ijiiiu'i'  ■>!'  \isioii 
lliriiiii,'li  Ihc  iiiiilJLili'il  |iii|>il. 

Ti)  Ihr  liJiMil  «iilc  iillil  J  lilllc  tiliiAC  Ihr  I'liil  iif  Ihi'  (Hm-  j,  [\„- 
iii.iiiii.ii-  ici;i((ii.  ;i  iliill-liiiiwii  cnilci-likc  ilcpriN^inii  IhiiiihIimI  liy  ,i 
xvliilc  iiiiis>  <>r  ri'lliM  Nlii;iliiiii>.  <>|)iii|iic  inT\i'  lilivo  r.iilijilc  Irdin 
liotli  sidcN  nf  llii-  ilJM-  lull  tiiiiiil.\  liisjippriir  m-.  IIkv  ;i|i|iri>;ii  Ii  Ihr 
lnMiiid.irics  of  I  III-  fiinilii-.. 

II.      I'liniilii. 
\\\.\  i    .l^^.      t  iiiiiiiirltlii  rrisliilii.      I'hilr  l,\l. 

Tlir  i;i'iiri;il  ciiicir  iif  llic  rycirnpiiiid  i>  :i  shilc-uniy,  with  :i  p;ilr- 
,\i-lli>H  liiil  ill  tin-  linMT  liiilr  of  till'  rvcfiroiind.  The  ciiliic  fiild  is 
Ipi'spiiiikird  willi  iri-ci:ill;ir!y  sliii|HMl.  Iij;lil-;;niy  dots,  niviiiy  il  l|i<- 
iipjMMiMiKc  of  H  roiiiili  iiiid  ml  her  coiii-sr  siii-f.-icc.  cspcciiillv   iiriir  the 

riiiiciikir  :iio;i    wlicic  llir  dol>  :iii-  i •,•  cIom'In-  piickcd  in   llii'  sliiipc 

of  »   liiifilil.  circiihir  p.ilcli. 

'riif  oplic  iiiTM'-lniid  is  (|iiilr  while  iiliil  of  oliloiiK  sliiipc.  SiviTiil 
oniiif;i'-<cilorcil.  (  hoioiihil  <;ipill,iri<'s  jirr  vi>il>lc  in  lliis  icj;iiiii.  Ih.ii  is 
rovcrrd  willi  iiiiiiiili'.  lnowii.  piijiiiciil  dols.  like  likick  pepper  i.'i;iiiis. 
Kxleiidiiii;  from  ciich  side  of  |  he  opi  ie  di>e  i>  n  kirire  iiiiiiilier  of 
opii<|iie  nerve  filires  Ih^il   evieiid  across  the  fiiiidiil  field. 

The  peeleii.  of  I  lie  iisii.il  <lio(ol;ile-lirow  ii  <-olor.  is  r.ilher  ineiiiihir 
ill  shiipe  III  ils  >ii|)erior  evlieiiiily.  From  .■il)o\e  downward  il  look> 
like  ,1  ship's  liirred  i;ilile.  Iiei  oiiiiii^'  hiriier  ,is  il  ^ippioiielies  il,  iiiiioii 
willi  the  pMpillii.  The  superior  eiiil  iippeMr,  to  eome  wc  II  into  Ihe 
vilreoiis  e,i\il\   nnd  lo  re:ieli  llii>  leiis. 


174  i 


CARINATiE 


Passeriformes 


I'ariiliii  liiiri 


Passerifonnes 


I'l.ATK   lA'I  ('!/iitit>iilta  crixlala 


il 


CARINATiE 

Passeriformes.     /'.     Coniilir. 

<(1MMII\    HlllTI>«ll    Hl.MKHIKII.       Tlirilllx  iinriild.       riiili- lAII. 

Till'  KciuTiil  liiil  of  IIk-  f,v<'Kriiiiiiil  is  ii  sIhI,v-k'"''\  «"""  "  imifoiiii 
■ipriiikliiiK  <>f  tinv.  wliili-  ilol;..     Tliiri-  is  iii>  visil»li-  iiiiiniliir  n-Kiim, 

lull  III!'  whoji'  f ills  is  covrrfd  anil  ils  colnriiiK  (.'rciillv  iiii>ilifii-il  li.v 

iiiiiiK-rniis  liiii'iir  iipiKiiii-  Kliri's  lliiil  iirisi-  frniii  llii'  liisi-  iiiiirt.'ins 
lliri>ii({lii>ul  iiiiil  niiimniss  llir  i-iilin- fuiiiliis  In  llii- i-xlrriiu- |)iri|)li<TV. 
A  fi'W.  fiiiiil.  yi'llinv-n-il  rlmroiilul  vi-ssils  iirr  si-i-ii  iiii  rillii-r  siilr  of 

iinil  imriillrl  li«  lli<-  i IitiiIi-Iv  Ii>ii»;  anil  luirruw  |ia|>illa.     Tlif  u|>|Mr 

l\Mi-lliiril>  i>f  I  Ik-  ilisr  is  aliiiill  lialf  riiviTi-ii  liv  llir  rliil>-sliii|M<l 
IM'clrli,  w  hirli  is  iiiiiiiiosimI  of  viTV  fi'W  fiilils.  Tin-  liiassivi-.  iliocKlalr- 
coliiri'il.  |Mislrriiir  riiil  nf  llir  |mtIi'Ii  mlirriv  olisniri-s  tlic  liiwrr  lliird 
i.f  ll:c  ilisc,  whilr  llir  iippiT  half  i>f  I  In'  foriniT  lias  a  Iiiiil  lirowii  liiar- 

;;i iu  nasal  ns|M'rl.  anil  sciins  In  lie  only  in  pari  allailinl  In   llir 

III  I". I'-lii-ail  l>rii<-alli  il. 

Hv\K\.     <'orrii.i  ninu.      I'lali'  lA'l  II. 

Till-  ••vitironnil  is  a  li^lil  fawn  sprinklcil  willi  ilols  al I  llin-r 

>lia(lrs  ilarkiT  limn  lliv  (.'niiinil  loliir.  Mixcil  willi  Ilii-  ilark  ilnis  an- 
a  ihiiiiImt  i)f  wliili-  oin-s.  scni  i's|M'(ially  wlit-ii  a  slnin^;  li^lil  is  llinnvii 
iipiMi  the  fiinilns.  Aliiml  llinr  (lisc-l.miilllis  fri.iii  llii-  iipiMr  i-iiil 
I.f  Ihc  ilisc  on  llir  iniiiT  siilc  is  a  wrll  niarkcil.  l.riKliI  ri-Hrx  of  a  «rrcii- 
ish-liliii'  liiiKc.  Il  is  irri-j;nlarly  oval  in  slia|H-  anil  sciMiis  lo  U-  luiii- 
posi'il  of  a  iiUMilM'r  of  VITV  fine  fitm-s.  In  llic  ci'iilrr  of  llir  ri-tlix  is 
Ilii-  inaiiila.  a  small,  ilark.  craliT-likt-  lii-pri'ssioii,  lirown  in  inlor. 
Till'  liisi-  is  ihalky  while,  anil  K'ivcs  oni-  I  hi-  iiiiprrssion  llial  il  is 
loniposid  of  many  opai|ui'  ihtvi-  filiri's  parki-ii  ilosi'ly  Iohi'IIkt. 
Krom  I  Ik-  ilisi-  margins  lln-rr  railiali-  a  iiiimlMT  of  fiiii'  opiic  iutvi- 
Kliri-s  Ihal  t'xli'iiil  across  llii-  i'yi').'ronnil.  In  llu-  Iowit  pari  of  llii- 
fiinilus.assiHiali-ilwilh  a  iiumlMTof  oraiifXi'-rnl  ih.ls.ari'a  ffw  oran>,'r- 
ri-il  choroiilal  l.h>oil-vi-s,.i.  .i-vi-ral  of  tin-  lalliT  Uv'mn  ili>lril)uliil 
alolin  i-illirr  si.ii"  of  '.li.'  -Iim  TIii'  |m-(I«-ii  is  very  lliin  anil  narrow 
al  the  ilisi' liul  as^iliiicsa  i  liili-shapc  as  il  approarhrs  lln'h-iis.  wliiTi- 
il  i^  ilarkrr  in  roloi.  Il  coiiii's  wi'll  forwaril  ami  appears  al  limes 
lo  press  a^iii'isl  llie  posterior  capsule  of  llie  lens. 


1761 


■•^r.T&'arvBSB^wj, 


CARINATJE 


Passeriformes 


I'l.ATF,  LVI! 


Tiirtliis  iiiiriila 


Passeriformes 


1'I.ATK  LYIIl 


I'orniH  corux 


.■i:\i&<i^£L  i 


s»5n«n»B*««w:«i»ianiifwr  iV"«eica«CTr«r.'»ynisf' ■-,  tiwi/s'*''^ 


yjimuKujevmatfS*  vivxKisim 


<  OLOUKI)   DH.WMMIS  OK  TIIF    FlNDl  S  (Ml  1,1   OK 
KKITII.KS, 

REPTILIA 

Tl  HK1»M    (iK(  Ko.      Ill  iiiiiliicll/liix  liiri'irii.1.      I'liili-  LIX. 

Till'  iii'iiiiKi'-riMl  ruiiiliis  i>  uiiiriirinly  tli>ttcil  witli  ihirk  >|hi|.h, 
while  lln-  circiiliir  |>j|>illii  In  coinplftrlv  olisciirt-il  Ity  IIh-  cliiM'tiliili-- 
lirnuii  ihtIcii,  uIiiim'  iHiiiilfil  free  rail  priiji-cts  ii  iiM'iliiiiii  (liMliiiicc 
into  llu-  vilri'iiiiM.  C'Iriirly  ilrfiiiril,  white  hiieiir  iiiediilhiteil  iierve- 
filire-  rniliiile  friiiii  the  ilise  iiiiir);iiis.  )>i\  iiit;  the  etfeet  ofii  lialii  iihoiit 
the  iTfilral  /i>iie  of  the  piitiiri'. 

lliiKNKK  ToAii.      I'liri/iiimiiiitii  iiirniitiim.      I'late  I,\. 

The  general  eoloraliiiii  of  I  lie  eyeuroiiiKJ  is  a  ilurk  .tlate.  irre^^u- 
larly  strewn  with  iiiiiiiile.  wliitiNli  clots  of  various  sizes.  There  is 
Mil  ill-ilefiiieil  iiiaciilar  re^jioti.  The  |H'ar-slia|M-<l,  );rayisli  papilla 
has  a  white  iiiar^'iii,  from  which  sho.t  tilires  of  iiiie'  'lal  leii);lli  radiate 
lowarils  tin- iH-ripiiery.  A  siiif;ii  -itral  ( i"!  arler-  'ems  to  originate 
from  (he  iiei  ve-liea<l  anil  with  its  six  liraliehes  iwi>  on  one  side  if 
the  disc,  four  on  the  other  is  supplied  mostly  In  the  low<-r  half  of 
the  tield.  A  small  liraiieh  anastomoses  aliove  with  a  twi^  that  runs 
from  the  |M'riphery  of  the  fundus. 


117HI 


ftA.-^'ifti  'BMBBfVfrr 


*!)■ 


"Tsw'Fr-^frTTrwr'asKT^aiffT' 


REPTILIA 


Turkish  Gecko 


Platk  I. IX  IIniii<liirt!/lii*  tiirrlciix 


Horned  Toad 


Plate  LX  Phrynomma  cornutnm 


^S5^SS5Bs?^^^^^^^^^^^^5?v? 


Ai..i.\\_. 


m/mim 


REPTILIA 

l\IH\S    <  i>llll\.       Xiliil  Irlliilililllli.       I'lillr   l/\l. 

Till'  p'Iii'imI  ciiliinitliiii  iif  till'  fiiiiilii^  iinili  in  llii->  Sn^ikr  i-.  li^lit 
(jnix  -liliic.  s|)iirM'lv  iliilli'il  vvilli  |(i;jiiii'iii  nf  ;i  >iiiiihir'  l)iil  <lrf|it'r  <iil(ir. 
Tlic  wliiilr  liiK'kKriiiiiHl  i>.  ri'Kiiliirlv  <ii\ crrd  willi  i>|>ii<|iii-  iinvc 
Hliii'>.  I'liiiii  till'  liiilloii-liki'  iiplic  (IIm-  iiii-f  llirrc  \rs>cl«.  ii|i|>iif- 
I'lillv  lull  :irlrri<"<  nf  <liliill  "i/r  iiiiil  iilir  liirurr  \i--><<rl  |iriiliiililv  ji 
vriii.  Tlir  (fill  rn  if  tlir  |iii|iillii  nIihw-  I  lie  ntiiiiili-.  iir  I  lir  iiMil('\i'lii|>ril 
llNMlri  iif  a  |M'('li'li. 


Iwi 


RBPTILU 


Indian  Cobra 


I'LATK  lAI 


Xai'a  Iri i>uditiii.i 


